Research Article Water Absorption and Thermomechanical Characterization...
8
Research Article Water Absorption and Thermomechanical Characterization of Extruded Starch/Poly(lactic acid)/Agave Bagasse Fiber Bioplastic Composites F. J. Aranda-García, R. González-Núñez, C. F. Jasso-Gastinel, and E. Mendizábal Departamento de Ingenier´ ıa Qu´ ımica, Centro Universitario de Ciencias Exactas e Ingenier´ ıas, Universidad de Guadalajara, Boulevard Marcelino Garc´ ıa Barrag´ an 1421, 44430 Guadalajara, JAL, Mexico Correspondence should be addressed to E. Mendiz´ abal; [email protected] Received 7 February 2015; Revised 16 June 2015; Accepted 18 June 2015 Academic Editor: Vijay K. akur Copyright © 2015 F. J. Aranda-Garc´ ıa et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Water absorption and thermomechanical behavior of composites based on thermoplastic starch (TPS) are presented in this work, wherein the concentration of agave bagasse fibers (ABF, 0–15 wt%) and poly(lactic acid) (PLA, 0–30 wt%) is varied. Glycerol (G) is used as starch (S) plasticizer to form TPS. Starch stands as the polymer matrix (70/30 wt/wt, S/G). e results show that TPS hygroscopicity decreases as PLA and fiber content increase. Storage, stress-strain, and flexural moduli increase with PLA and/or agave bagasse fibers (ABF) content while impact resistance decreases. e TPS glass transition temperature increases with ABF content and decreases with PLA content. Micrographs of the studied biocomposites show a stratified brittle surface with a rigid fiber fracture. 1. Introduction Nowadays, the interest in bioplastics is growing for mar- ket niches such as packaging, agriculture, or automotive parts among others. ey are classified in biodegradable and biobased/nonbiodegradable. In 2014, their total global production capacity reached 1.67 million tons, where 643,000 tons corresponded to biodegradable plastics [1]. By 2018, the production capacity is expected to reach more than 6 million tons, where 1.06 million will correspond to the biodegradable type [1]. e main sources of biomass to produce bioplastics are grains (usually corn), sugar cane bagasse, potatoes, and castor oil. It is reported that other natural sources such as cellulose and corn stover will also become an important raw material [1]. Since starch (S) is an economical biopolymer that is contained in many natural products, it is attractive as a source to make biodegradable plastics [2]. In dry form, depending on the source and characterization method, starch shows a melting temperature ( ) that varies from 200 ∘ C[2] to 220 [3] or even 240 ∘ C[4]; however, with 10 % of humidity, its decreases to 160 ∘ C[3]. It is mainly composed of amylose and amylopectin which show very different physical and chemical properties [2, 4, 5]. Starch has to be plasticized to lower its high [3] and processing temperature to avoid degradation before [6] it melts. Plastification with water, glycerol, sorbitol, sugars, or amino acids lowers its and its glass transition temperature ( )[6] forming a thermoplastic starch (TPS) and increasing its moldability. Glycerol (G) is the plasticizer most commonly used for starch in proportions ranging from 20 to 50% by weight. Unfortunately, materials based on starch have low mechanical properties because of its hydrophilic character [7–9]. To overcome that problem, TPS has been mixed with other polymers (forming polymer blends) [3, 4], or with reinforcing agents (e.g., natural or synthetic fibers) [2, 5, 7]. Natural fibers as reinforcing materials offer some advantages; among them the following may be mentioned: improvement of some mechanical properties of the polymer matrix [10, 11], minimization of environmental pollution [9], and lower production costs; however, natural fibers present the limitation that processing temperatures are restricted to less than 200 ∘ C. Hindawi Publishing Corporation International Journal of Polymer Science Volume 2015, Article ID 343294, 7 pages http://dx.doi.org/10.1155/2015/343294
Transcript of Research Article Water Absorption and Thermomechanical Characterization...
Research ArticleWater Absorption and ThermomechanicalCharacterization of Extruded StarchPoly(lactic acid)AgaveBagasse Fiber Bioplastic Composites
F J Aranda-Garciacutea R Gonzaacutelez-Nuacutentildeez C F Jasso-Gastinel and E Mendizaacutebal
Departamento de Ingenierıa Quımica Centro Universitario de Ciencias Exactas e Ingenierıas Universidad de GuadalajaraBoulevard Marcelino Garcıa Barragan 1421 44430 Guadalajara JAL Mexico
Correspondence should be addressed to E Mendizabal lalomendizabalhotmailcom
Received 7 February 2015 Revised 16 June 2015 Accepted 18 June 2015
Academic Editor Vijay K Thakur
Copyright copy 2015 F J Aranda-Garcıa et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited
Water absorption and thermomechanical behavior of composites based on thermoplastic starch (TPS) are presented in this workwherein the concentration of agave bagasse fibers (ABF 0ndash15wt) and poly(lactic acid) (PLA 0ndash30wt) is varied Glycerol (G)is used as starch (S) plasticizer to form TPS Starch stands as the polymer matrix (7030wtwt SG) The results show that TPShygroscopicity decreases as PLA and fiber content increase Storage stress-strain and flexural moduli increase with PLA andoragave bagasse fibers (ABF) content while impact resistance decreases The TPS glass transition temperature increases with ABFcontent and decreases with PLA content Micrographs of the studied biocomposites show a stratified brittle surface with a rigidfiber fracture
1 Introduction
Nowadays the interest in bioplastics is growing for mar-ket niches such as packaging agriculture or automotiveparts among others They are classified in biodegradableand biobasednonbiodegradable In 2014 their total globalproduction capacity reached 167million tons where 643000tons corresponded to biodegradable plastics [1] By 2018 theproduction capacity is expected to reach more than 6 milliontons where 106million will correspond to the biodegradabletype [1] The main sources of biomass to produce bioplasticsare grains (usually corn) sugar cane bagasse potatoes andcastor oil It is reported that other natural sources such ascellulose and corn stover will also become an important rawmaterial [1]
Since starch (S) is an economical biopolymer that iscontained inmany natural products it is attractive as a sourceto make biodegradable plastics [2] In dry form dependingon the source and characterization method starch shows amelting temperature (119879
119898) that varies from 200∘C [2] to 220
[3] or even 240∘C [4] however with 10 of humidity its 119879119898
decreases to 160∘C [3] It is mainly composed of amylose and
amylopectinwhich show very different physical and chemicalproperties [2 4 5]
Starch has to be plasticized to lower its high 119879119898[3] and
processing temperature to avoid degradation before [6] itmelts Plastification with water glycerol sorbitol sugars oramino acids lowers its 119879
119898and its glass transition temperature
(119879119892) [6] forming a thermoplastic starch (TPS) and increasing
itsmoldability Glycerol (G) is the plasticizermost commonlyused for starch in proportions ranging from 20 to 50 byweight Unfortunately materials based on starch have lowmechanical properties because of its hydrophilic character[7ndash9] To overcome that problem TPS has been mixedwith other polymers (forming polymer blends) [3 4] orwith reinforcing agents (eg natural or synthetic fibers)[2 5 7] Natural fibers as reinforcing materials offer someadvantages among them the following may be mentionedimprovement of some mechanical properties of the polymermatrix [10 11] minimization of environmental pollution [9]and lower production costs however natural fibers presentthe limitation that processing temperatures are restricted toless than 200∘C
Hindawi Publishing CorporationInternational Journal of Polymer ScienceVolume 2015 Article ID 343294 7 pageshttpdxdoiorg1011552015343294
2 International Journal of Polymer Science
Table 1 Composite formulations
S g G g TPSlowast g PLA g ABF g PLA wt in polymer blende ABF wt in composite998787
70 30 100 0 0 0 063 27 90 10 0 10 056 24 80 20 0 20 049 21 70 30 0 30 070 30 100 0 1111 0 1063 27 90 10 1111 10 1056 24 80 20 1111 20 1049 21 70 30 1111 30 1070 30 100 0 1765 0 1563 27 90 10 1765 10 1556 24 80 20 1765 20 1549 21 70 30 1765 30 15lowastTPS represents the mixture of S and G ePolymer blend represents the mixture of TPS and PLA 998787Composite represents the mixture of TPS PLA and ABF
Dufresne and Vignon in an early work on starchfibercomposites reported that thermomechanical properties ofpotato starch films were improved when they were mixedwith cellulose nanofibers showing also a decrease inmoisturesensitivity while maintaining biodegradability Additionallythey found that increasing the glycerol content the equilib-rium moisture increased and that such parameter decreasedwhen the fiber content was augmented [5]
Huneault and Li studied mixtures of TPS with poly(lacticacid) (PLA) using maleic acid as a compatibilizer Theyreported that Young modulus (119864) and tensile strengthincreased when PLA content was increased [12] An increasein 119864 and tensile strength of TPS was reported usingpoly(lactic acid) fibrillation for reinforcement [13]
Although there are several works that follow the effect ofPLA or natural fibers onmoisture absorption andmechanicalproperties of TPS there are very few reports on the effectof the simultaneous addition of both materials to the TPSFurthermore there is only scarce data on properties of TPScomposites containing cellulosic fibers that were obtained asa byproduct of an industrial process Teixeira et al reportedthe use of cassava bagasse to obtain fiber reinforced TPSand PLATPS blends but tensile strength did not increasesignificantly and the fiber essentially acted as a filler [14]Castano et al found that reinforcing a TPSPLAPVA blendwith pehuen cellulosic husk the increase on mechanicalproperties was small [15] Using pineapple fibers in TPSPLAblends an improvement in mechanostatic properties andwater resistance was reported [16] Cellulose derivatives havealso been used to reinforce starch [17]
Using PLA [18 19] or PCL [20] as polymer matrix withagave sisalana (sisal) as reinforcer the results showed anincrease in storage [18 19] flexural [18] and tensile moduli[20]
In this work the effects of the amount of PLA andoragave bagasse fibers on moisture absorption and mechanicaland thermal properties of TPS are reported This is the firstreport on the application of agave bagasse fibers to reinforceTPSPLA blends which are discarded fibers from industrialprocesses
2 Experimental
21 Materials The materials used in this work were cornstarch (IMSA) with 10 humidity glycerol QP (GoldenBell Products) agave bagasse (tequilana Weber blue var)fiber PLA (Ingeo Biopolymer 3521D Industries Leben) andMagnesium Nitrate (Fermont) To prepare TPS after thestarch was dried for 24 h at 60∘C it was manually mixed withglycerol (30wt) until a homogeneousmixturewas obtainedTPS was mixed with different amounts of PLA andor fiber(Table 1) in a corotating twin-screw extruder (LeistritzMicro27 equipment GLGG 32D) to obtain a continuous cordof polymer blend or composites that were pelletized afterextrusion The pellets of the different materials were firstdried at 60∘C until a constant weight was obtained then theywere molded by thermal compression in a SchwabenthanPolystat 200T compression equipment at 180∘C and 200 barsduring 25minutesmaintaining pressure for 10moreminutesduring the cooling stage
22 Equilibrium Moisture First composites were dried at60∘C for 24 h then the material was weighed and placed at25∘C in a closed chambermaintained at a relative humidity of53 (saturated solution of magnesium nitrate) The compos-ites weight was recorded periodically until a constant weightwas obtained
23 Mechanical Tests Mechanodynamic tests were carriedout following ASTM D5023-01 using a thermomechanicalanalyzer (TAQ800DMA) and the following conditions tem-perature range minus85∘C to 150∘C heating rate 2∘Cmin three-point bending clamp and frequency of 1Hz Mechanostatictests were carried out at 25∘C following ASTM D638-04for stress-strain (Instron 4411 crosshead speed 5mmmin)ASTMD790-03 for flexure (Instron 4411) and ASTMD6110-04 (Instron Ceast 9050) for Charpy impact testing
24 Thermal Characterization Thermal behavior of thesamples was followed by DSC (Q Series DSC Q100 TA
International Journal of Polymer Science 3
Time (days)0 5 10 15 20 25
Wat
er ab
sorp
tion
(wt
)
0
3
6
9
12
15
Fiber content (wt)0
10
15
Figure 1 Moisture absorption of TPSPLAFiber composites as afunction of time for the polymer blend and composites containing20wt PLA
Instruments) using ASTM D3418-03 Heating rate was10∘Cmin from 20 to 180∘C
25 Morphology Samples were observed by Field EmissionScanning Electronic Microscopy (FE-SEM (Tescan Mira3))The samples were frozen in liquid nitrogen for 5 minutesbefore fracture Subsequently the samples were dried at 60∘Cbefore FE-SEM observation
3 Results
31 Moisture Absorption Figure 1 shows moisture absorp-tion of the polymer blend and the composites containing20wt PLA Such figure illustrates that the rate of moistureabsorption decreases as the ABF content increases and thatequilibrium is reached in approximately two weeks Similarmoisture absorption behavior was obtained for the othermaterials
For moisture absorption it can also be noticed that anincrease in ABF content reduces the equilibrium moisturevalue (Figure 2) that behavior can be explained in terms ofthe lower hydrophilic character of the fiber comparing withtheTPS Like in this case it has been reported that compositesof TPS with sugarcane bagasse fibers showed a decreasein moisture equilibrium when fiber content was increased[21] Additionally since PLA is a less hydrophilic polymerthan TPS independently of fiber content increasing PLAconcentration causes a decrease in the moisture absorptioncapacity of the composite (Figure 2)
32 Thermomechanical Analysis In Figure 3 the storagemodulus (1198641015840) is presented as a function of temperature for thecomposites containing 20wt of PLAThere an overlappingplateau for the 3 samples can be observed from minus30 to 40∘C
Poly(lactic acid) content (wt)0 10 20 30
Wat
er ab
sorp
tion
(wt
)
0
2
4
6
8
10
ABF content (wt)0
10
15
Figure 2 Equilibrium moisture of polymer blends and compositesvarying PLA content
Stor
age m
odul
us (E
998400) (
MPa
)
1e + 5
1e + 4
1e + 3
1e + 2
1e + 1
minus90 minus40 10 60 110 160
Temperature (∘C)
ABF content (wt)0
10
15
Figure 3 Storage modulus as a function of temperature for thepolymer blend and composites containing 20wt of PLA
however the composites maintain the plateau 1198641015840 value forabout 10∘C more than the polymer blend Such additionaltemperature resistance before 1198641015840 decay is important foroutdoor thermoplastic applications and indicates that thefiber acts as a reinforcing material due to its rigidity andhydrogen bonding between the polymer blend and the ABFSimilar storage modulus behavior was obtained for the othercomposites Such type of effect has been reported for TPSreinforced with cellulose fibers [22]
The storage modulus at 25∘C of the studied composites isshown in Figure 4 Such figure indicates that higher storagemoduli are obtained with the inclusion of ABF andor PLAand such increase is larger as more PLA andor ABF areadded The reinforcement effect of PLA and ABF along withhydrogen bonding leads to a decrease in chains mobility It
4 International Journal of Polymer Science
6000
5000
4000
3000
2000
1000
0
0 10 20 30
Stor
age m
odul
us (E
998400) (
MPa
)
Poly(lactic acid) content (wt)
ABF content (wt)0
10
15
Figure 4 Storage modulus of polymer blends and composites at25∘C varying PLA content
minus90 minus40 10 60 110 160000
005
010
015
020
025
030
035
040
Temperature (∘C)
tan 120575
ABF content (wt)0
10
15
Figure 5 tan 120575 versus temperature for polymer blend and compos-ites containing 20wt PLA
has been reported that modulus increases with fiber content[7 22 23] due to the high compatibility between TPS andcellulose fillers [5 10] Reports about it include bleachedleaf wood fibers [24] fibers from bleached eucalyptus pulp[25] flax and ramie fibers [26] wood pulp [27] and tunicinwhiskers [28ndash30]
Figure 5 shows tan 120575 versus temperature for the com-posites containing 20wt of PLA This figure shows thatthe peaks appear in three regions (a) around minus55∘C (119879
119892of
glycerol) (b) at 54ndash57∘C which is attributed to 119879119892of PLA
and (c) at 115ndash130∘C that corresponds to 119879119892of S
Table 2 119879119892of starch in polymer blends and composites
PLA content in polymerblend wt
ABF content in composites wt0 10 15
10 120∘C 124∘C 132∘C20 115∘C 120∘C 130∘C30 111∘C 114∘C 127∘C
0 50 100 150 200
Hea
t flow
(Wg
)00
01
02
03
04
05
06
Temperature (∘C)
Fiber content (wt)0
10
15
Figure 6 Thermograms of the polymer blend and compositescontaining 20wt of PLA
Using tan 120575 results of the polymer blend and compositescontaining different amounts of PLA and ABF the 119879
119892values
of TPS are presented in Table 2 The values indicate that anincrease in PLA content promotes a decrease in 119879
119892 such
behavior can be explained by the lower 119879119892value of PLA
compared to that of the starch (119879119892gt 110∘C) [3 4] In Table 2 it
can also be noticed that for constant PLA content there is anincrease in 119879
119892as fiber content increases the 119879
119892displacement
can be attributed to the decrease of starch chainsmobility andthe H-bond interactions between ABF and TPS [7 22 24]
33 Thermal Analysis The DSC thermogram (Figure 6)shows the thermal transitions of the polymer blend andcomposites containing 20wt of PLA For the curves atapproximately 60∘C a change in slope can be observed dueto the 119879
119892of PLA Those temperature values are presented
in Table 3 The small decrement in 119879119892for the composites
with respect to the pure PLA obtained here (62∘C) can beattributed to glycerin migration as Li and Huneault reported[31] In addition Martin and Averous reported a smalldecrease in119879
119892of PLA by the presence of glycerol [32] For the
composites containing the larger amount of fiber (15 wt)the119879119892of PLA shows a slight decrease by enhanced PLA chain
mobility Jaafar et al reported a decrease in 119879119892of PLA which
International Journal of Polymer Science 5
Table 3 119879119892of PLA in polymer blends and composites
PLA content in polymerblend wt
ABF content in composites wt0 10 15
10 570∘C 571∘C 545∘C20 570∘C 573∘C 555∘C30 570∘C 570∘C 560∘C
Table 4 119879119888of PLA in polymer blends and composites
PLA content in polymerblend wt
ABF content in composites wt0 10 15
10 1000∘C 1007∘C 991∘C20 999∘C 998∘C 1010∘C30 989∘C 1004∘C 1002∘C
Table 5 119879119898of PLA in polymer blends and composites
PLA content in polymerblend wt
ABF content in composites wt0 10 15
10 1630∘C 1645∘C 1610∘C20 1659∘C 1636∘C 1634∘C30 1661∘C 1659∘C 1632∘C
they attributed to the inclusion of Kenaf fibers that increasedPLA chains mobility because fibers separate PLA chains [33]
The exothermic peak that appears at approximately 100∘Cis related to PLA crystallization (119879
119888) as a result of the
interaction of PLA and TPS [32] 119879119888values are shown in
Table 4 where no noticeable effect can be seen for a fiber orPLA concentration increase (equivalent to TPS concentrationdecrease) Teixeira et al reported a small decrease in the119879
119888of
PLA using cassava bagasse [14]For the polymeric materials of Figure 6 the small vari-
ation in the slope of the curves indicates that the 119879119892of S
appears at 110ndash130∘C Those values correspond to the tan 120575peaks shown in Figure 5
Figure 6 also shows peaks between 110 and 130∘Cdue to119879119892
of starch which coincide with the 119879119892obtained by mechano-
dynamic tests which confirms that increasing fiber contentincreases 119879
119892
The endothermic peaks at the high temperature zonecorrespond to PLAmelting temperature (119879
119898) The peak tem-
perature values presented in Table 5 show that slight changesin PLA melting temperature correspond to an increase withPLA content and a decreasewithABF addition Such decreasecan be explained by the interference that fibers may cause toallow PLA crystallization Before the PLA melting peaks thecorrespondent small shoulder is attributed to rearrangementof lamellar fractions formed during PLA crystallization [34]or premelting of small crystals
34 Mechanostatical Tests Even though mechanodynamictests allowed the thermomechanical characterization of
Poly(lactic acid) (wt)0 10 20
Youn
g m
odul
us (M
Pa)
0
100
200
300
400
500
600
ABF content (wt)0
10
15
Figure 7 Young modulus of polymer blends and composites at25∘C varying PLA content
Poly(lactic acid) (wt)0 10 20
Flex
ural
mod
ulus
(MPa
)
0
500
1000
1500
2000
2500
3000
3500
ABF content (wt)0
10
15
Figure 8 Flexural modulus of polymer blends and composites at25∘C varying PLA content
extruded materials mechanostatic tests of some of the com-posites are included to confirm their moduli values patternas well as to determine impact resistance behavior In Figure 7Young modulus of polymer blends and composites as afunction of PLA and fiber content is shown The inclusionof PLA andor ABF promotes an increase in modulus Thosepatterns are in agreement with the storage modulus valuesobtained at 25∘C (Figure 4)
Figure 8 shows flexural modulus of the polymeric materi-als as a function of PLA and fiber content For this parameteran increase in PLA andor fiber content leads to composites
6 International Journal of Polymer Science
Poly(lactic acid) content (wt)0 10 20
0
2
4
6
8
10
12
14
16
18Im
pact
resis
tanc
e (kJ
m2)
Fiber content (wt)0
10
15
Figure 9 Impact resistance of polymer blends and composites at25∘C varying PLA content
with higher flexuralmodulus supporting the results obtainedfor the other moduli
In Figure 9 it can be noticed that the increase in rigidityof the TPS caused by the addition of PLA andor ABF leadsto a large decrease in impact resistance
35 Morphology In Figure 10 micrographs of fractured sam-ples of (a) TPS (b) polymer blend containing 20wt of PLAand (c) 80 TPS20 PLA ww with 15 wt ABF composite areshown In Figure 10(a) uniform gelatinized starch granulescan be observed Figure 10(b) shows a stratified brittle surfaceThe fibers in the composite can be seen in Figure 10(c) and arigid fracture is noticed
4 Conclusions
Blends of TPS and PLA and composites of TPSPLAABFprepared by extrusion followed by compressionmoldingwerecharacterized The reinforcing effect of PLA andor ABF inTPS led to an increase in moduli and a decrease in moistureabsorption and impact resistance The TPS glass transitiontemperature increased with ABF content and decreased withPLA content
The reinforcing effect of PLA was enhanced by theincorporation of ABF although the reduction in impactresistance is not convenientThat kind of behavior is expectedgenerically for rigidmaterials nevertheless thewood appear-ance and biodegradability along with the increase in modulias well as thermal resistance and the decrease in waterabsorption justify the production of this type of compositesfor many applications
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
(a)
(b)
(c)
Figure 10 SEM images of polymericmaterials (a) TPS (b) polymerblend containing 20wt PLA and (c) 80 TPS20 PLA ww with15 wt ABF composite
Acknowledgment
F J Aranda-Garcıa acknowledges CONACYT for a scholar-ship
International Journal of Polymer Science 7
References
[1] Institute for Bioplastics and Biocomposites and Nova-InstituteMore Bioplastic Statistic European Bioplastics 2014 httpwwwbio-basedeumarkets
[2] J L Guimaraes F Wypych C K Saul L P Ramos and K GSatyanarayana ldquoStudies of the processing and characterizationof corn starch and its composites with banana and sugarcanefibers from Brazilrdquo Carbohydrate Polymers vol 80 no 1 pp130ndash138 2010
[3] H Wang X Sun and P Seib ldquoEffects of starch moisture onproperties of wheat starchpoly (lactic acid) blend containingmethylenediphenyl diisocyanaterdquo Journal of Polymers and theEnvironment vol 10 no 4 pp 133ndash138 2002
[4] P Sarazin G Li W J Orts and B D Favis ldquoBinary andternary blends of polylactide polycaprolactone and thermo-plastic starchrdquo Polymer vol 49 no 2 pp 599ndash609 2008
[5] A Dufresne and M R Vignon ldquoImprovement of starch filmperformances using cellulosemicrofibrilsrdquoMacromolecules vol31 no 8 pp 2693ndash2696 1998
[6] H Liu F Xie L Yu L Chen and L Li ldquoThermal processing ofstarch-based polymersrdquo Progress in Polymer Science vol 34 no12 pp 1348ndash1368 2009
[7] J Girones J P Lopez P Mutje A J F Carvalho A A SCurvelo and F Vilaseca ldquoNatural fiber-reinforced thermoplas-tic starch composites obtained by melt processingrdquo CompositesScience and Technology vol 72 no 7 pp 858ndash863 2012
[8] R L Shogren ldquoPoly(ethylene oxide)-coated granular starch-poly(hydroxybutyrate-co-hydroxyvalerate) composite materi-alsrdquo Journal of Environmental Polymer Degradation vol 3 no2 pp 75ndash80 1995
[9] L Yu K Dean and L Li ldquoPolymer blends and composites fromrenewable resourcesrdquo Progress in Polymer Science vol 31 no 6pp 576ndash602 2006
[10] A Dufresne D Dupeyre and M R Vignon ldquoCellulosemicrofibrils from potato tuber cells processing and character-ization of starchndashcellulose microfibril compositesrdquo Journal ofApplied Polymer Science vol 76 no 14 pp 2080ndash2092 2000
[11] M J John and S Thomas ldquoBiofibres and biocompositesrdquoCarbohydrate Polymers vol 71 no 3 pp 343ndash364 2008
[12] M A Huneault andH Li ldquoMorphology and properties of com-patibilized polylactidethermoplastic starch blendsrdquo Polymervol 48 no 1 pp 270ndash280 2007
[13] L Jiang B Liu and J Zhang ldquoNovel high-strength thermo-plastic starch reinforced by in situ poly(lactic acid) fibrillationrdquoMacromolecular Materials and Engineering vol 294 no 5 pp301ndash305 2009
[14] E D M Teixeira A A S Curvelo A C Correa J MMarconcini G M Glenn and L H C Mattoso ldquoProperties ofthermoplastic starch from cassava bagasse and cassava starchand their blends with poly (lactic acid)rdquo Industrial Crops andProducts vol 37 no 1 pp 61ndash68 2012
[15] J Castano S Rodrıguez-Llamazares C Carrasco andR BouzaldquoPhysical chemical and mechanical properties of pehuen cellu-losic husk and its pehuen-starch based compositesrdquo Carbohy-drate Polymers vol 90 no 4 pp 1550ndash1556 2012
[16] W Smitthipong R Tantatherdtam and R Chollakup ldquoEffect ofpineapple leaf fiber-reinforced thermoplastic starchpoly(lacticacid) green composite mechanical viscosity and water resis-tance propertiesrdquo Journal ofThermoplastic CompositeMaterialsvol 28 no 5 pp 717ndash729 2015
[17] V A Alvarez and A Vazquez ldquoThermal degradation of cel-lulose derivativesstarch blends and sisal fibre biocompositesrdquoPolymerDegradation and Stability vol 84 no 1 pp 13ndash21 2004
[18] M Prajer and M P Ansell ldquoThermomechanical evaluation ofsisal-PLA compositesrdquo in Proceedings of the 17th InternationalConference on Composite Materials (ICCM rsquo09) pp 27ndash31 July2009
[19] E E M Ahmad and A S Luyt ldquoMorphology thermaland dynamic mechanical properties of poly(lactic acid)sisalwhisker nanocompositesrdquoPolymerComposites vol 33 no 6 pp1025ndash1032 2012
[20] A Campos K B R Teodoro E M Teixeira et al ldquoPropertiesof thermoplastic starch and TPSpolycaprolactone blend rein-forced with sisal whiskers using extrusion processingrdquo PolymerEngineering amp Science vol 53 no 4 pp 800ndash808 2013
[21] M E Vallejos A A S Curvelo EM Teixeira et al ldquoCompositematerials of thermoplastic starch and fibers from the ethanol-water fractionation of bagasserdquo Industrial Crops and Productsvol 33 no 3 pp 739ndash746 2011
[22] L Averous and N Boquillon ldquoBiocomposites based on plas-ticized starch thermal and mechanical behavioursrdquo Carbohy-drate Polymers vol 56 no 2 pp 111ndash122 2004
[23] R Belhassen S Boufi F Vilaseca et al ldquoBiocomposites basedon Alfa fibers and starch-based biopolymerrdquo Polymers forAdvanced Technologies vol 20 no 12 pp 1068ndash1075 2009
[24] L Averous C Fringant and L Moro ldquoPlasticized starch-cellulose interactions in polysaccharide compositesrdquo Polymervol 42 no 15 pp 6565ndash6572 2001
[25] A A S Curvelo A J F De Carvalho and J A M AgnellildquoThermoplastic starch-cellulosic fibers composites preliminaryresultsrdquoCarbohydrate Polymers vol 45 no 2 pp 183ndash188 2001
[26] M Wollerdorfer and H Bader ldquoInfluence of natural fibreson the mechanical properties of biodegradable polymersrdquoIndustrial Crops and Products vol 8 no 2 pp 105ndash112 1998
[27] A J F de Carvalho A A S Curvelo and J A M AgnellildquoWood pulp reinforced thermoplastic starch compositesrdquo Inter-national Journal of Polymeric Materials vol 51 no 7 pp 647ndash660 2002
[28] M N Angles and A Dufresne ldquoPlasticized starchtunieinwhiskers nanocomposites 1 Structural analysisrdquoMacromolecu-les vol 33 no 22 pp 8344ndash8353 2000
[29] M N Angles and A Dufresne ldquoPlasticized starchtunicinwhiskers nanocomposite materials 2 Mechanical behaviorrdquoMacromolecules vol 34 no 9 pp 2921ndash2931 2001
[30] A P Mathew and A Dufresne ldquoMorphological investigationof nanocomposites from sorbitol plasticized starch and tunicinwhiskersrdquo Biomacromolecules vol 3 no 3 pp 609ndash617 2002
[31] H Li andM A Huneault ldquoComparison of sorbitol and glycerolas plasticizers for thermoplastic starch in TPSPLA blendsrdquoJournal of Applied Polymer Science vol 119 no 4 pp 2439ndash24482011
[32] O Martin and L Averous ldquoPoly(lactic acid) plasticization andproperties of biodegradable multiphase systemsrdquo Polymer vol42 no 14 pp 6209ndash6219 2001
[33] W Jaafar W N Raihan S Siti Norasmah et al ldquoThermalproperties of PLAKenaf green nanocomposite effect of chemi-mechanical treatmentrdquo Advanced Materials Research vol 576pp 342ndash344 2012
[34] C Way D Y Wu D Cram K Dean and E Palombo ldquoPro-cessing stability and biodegradation of polylactic Acid (PLA)composites reinforced with cotton linters or maple hardwoodfibresrdquo Journal of Polymers and the Environment vol 21 no 1pp 54ndash70 2013
Submit your manuscripts athttpwwwhindawicom
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CorrosionInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Polymer ScienceInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CeramicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CompositesJournal of
NanoparticlesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Biomaterials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
NanoscienceJournal of
TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of
NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
CrystallographyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CoatingsJournal of
Advances in
Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Smart Materials Research
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MetallurgyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BioMed Research International
MaterialsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nano
materials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofNanomaterials
2 International Journal of Polymer Science
Table 1 Composite formulations
S g G g TPSlowast g PLA g ABF g PLA wt in polymer blende ABF wt in composite998787
70 30 100 0 0 0 063 27 90 10 0 10 056 24 80 20 0 20 049 21 70 30 0 30 070 30 100 0 1111 0 1063 27 90 10 1111 10 1056 24 80 20 1111 20 1049 21 70 30 1111 30 1070 30 100 0 1765 0 1563 27 90 10 1765 10 1556 24 80 20 1765 20 1549 21 70 30 1765 30 15lowastTPS represents the mixture of S and G ePolymer blend represents the mixture of TPS and PLA 998787Composite represents the mixture of TPS PLA and ABF
Dufresne and Vignon in an early work on starchfibercomposites reported that thermomechanical properties ofpotato starch films were improved when they were mixedwith cellulose nanofibers showing also a decrease inmoisturesensitivity while maintaining biodegradability Additionallythey found that increasing the glycerol content the equilib-rium moisture increased and that such parameter decreasedwhen the fiber content was augmented [5]
Huneault and Li studied mixtures of TPS with poly(lacticacid) (PLA) using maleic acid as a compatibilizer Theyreported that Young modulus (119864) and tensile strengthincreased when PLA content was increased [12] An increasein 119864 and tensile strength of TPS was reported usingpoly(lactic acid) fibrillation for reinforcement [13]
Although there are several works that follow the effect ofPLA or natural fibers onmoisture absorption andmechanicalproperties of TPS there are very few reports on the effectof the simultaneous addition of both materials to the TPSFurthermore there is only scarce data on properties of TPScomposites containing cellulosic fibers that were obtained asa byproduct of an industrial process Teixeira et al reportedthe use of cassava bagasse to obtain fiber reinforced TPSand PLATPS blends but tensile strength did not increasesignificantly and the fiber essentially acted as a filler [14]Castano et al found that reinforcing a TPSPLAPVA blendwith pehuen cellulosic husk the increase on mechanicalproperties was small [15] Using pineapple fibers in TPSPLAblends an improvement in mechanostatic properties andwater resistance was reported [16] Cellulose derivatives havealso been used to reinforce starch [17]
Using PLA [18 19] or PCL [20] as polymer matrix withagave sisalana (sisal) as reinforcer the results showed anincrease in storage [18 19] flexural [18] and tensile moduli[20]
In this work the effects of the amount of PLA andoragave bagasse fibers on moisture absorption and mechanicaland thermal properties of TPS are reported This is the firstreport on the application of agave bagasse fibers to reinforceTPSPLA blends which are discarded fibers from industrialprocesses
2 Experimental
21 Materials The materials used in this work were cornstarch (IMSA) with 10 humidity glycerol QP (GoldenBell Products) agave bagasse (tequilana Weber blue var)fiber PLA (Ingeo Biopolymer 3521D Industries Leben) andMagnesium Nitrate (Fermont) To prepare TPS after thestarch was dried for 24 h at 60∘C it was manually mixed withglycerol (30wt) until a homogeneousmixturewas obtainedTPS was mixed with different amounts of PLA andor fiber(Table 1) in a corotating twin-screw extruder (LeistritzMicro27 equipment GLGG 32D) to obtain a continuous cordof polymer blend or composites that were pelletized afterextrusion The pellets of the different materials were firstdried at 60∘C until a constant weight was obtained then theywere molded by thermal compression in a SchwabenthanPolystat 200T compression equipment at 180∘C and 200 barsduring 25minutesmaintaining pressure for 10moreminutesduring the cooling stage
22 Equilibrium Moisture First composites were dried at60∘C for 24 h then the material was weighed and placed at25∘C in a closed chambermaintained at a relative humidity of53 (saturated solution of magnesium nitrate) The compos-ites weight was recorded periodically until a constant weightwas obtained
23 Mechanical Tests Mechanodynamic tests were carriedout following ASTM D5023-01 using a thermomechanicalanalyzer (TAQ800DMA) and the following conditions tem-perature range minus85∘C to 150∘C heating rate 2∘Cmin three-point bending clamp and frequency of 1Hz Mechanostatictests were carried out at 25∘C following ASTM D638-04for stress-strain (Instron 4411 crosshead speed 5mmmin)ASTMD790-03 for flexure (Instron 4411) and ASTMD6110-04 (Instron Ceast 9050) for Charpy impact testing
24 Thermal Characterization Thermal behavior of thesamples was followed by DSC (Q Series DSC Q100 TA
International Journal of Polymer Science 3
Time (days)0 5 10 15 20 25
Wat
er ab
sorp
tion
(wt
)
0
3
6
9
12
15
Fiber content (wt)0
10
15
Figure 1 Moisture absorption of TPSPLAFiber composites as afunction of time for the polymer blend and composites containing20wt PLA
Instruments) using ASTM D3418-03 Heating rate was10∘Cmin from 20 to 180∘C
25 Morphology Samples were observed by Field EmissionScanning Electronic Microscopy (FE-SEM (Tescan Mira3))The samples were frozen in liquid nitrogen for 5 minutesbefore fracture Subsequently the samples were dried at 60∘Cbefore FE-SEM observation
3 Results
31 Moisture Absorption Figure 1 shows moisture absorp-tion of the polymer blend and the composites containing20wt PLA Such figure illustrates that the rate of moistureabsorption decreases as the ABF content increases and thatequilibrium is reached in approximately two weeks Similarmoisture absorption behavior was obtained for the othermaterials
For moisture absorption it can also be noticed that anincrease in ABF content reduces the equilibrium moisturevalue (Figure 2) that behavior can be explained in terms ofthe lower hydrophilic character of the fiber comparing withtheTPS Like in this case it has been reported that compositesof TPS with sugarcane bagasse fibers showed a decreasein moisture equilibrium when fiber content was increased[21] Additionally since PLA is a less hydrophilic polymerthan TPS independently of fiber content increasing PLAconcentration causes a decrease in the moisture absorptioncapacity of the composite (Figure 2)
32 Thermomechanical Analysis In Figure 3 the storagemodulus (1198641015840) is presented as a function of temperature for thecomposites containing 20wt of PLAThere an overlappingplateau for the 3 samples can be observed from minus30 to 40∘C
Poly(lactic acid) content (wt)0 10 20 30
Wat
er ab
sorp
tion
(wt
)
0
2
4
6
8
10
ABF content (wt)0
10
15
Figure 2 Equilibrium moisture of polymer blends and compositesvarying PLA content
Stor
age m
odul
us (E
998400) (
MPa
)
1e + 5
1e + 4
1e + 3
1e + 2
1e + 1
minus90 minus40 10 60 110 160
Temperature (∘C)
ABF content (wt)0
10
15
Figure 3 Storage modulus as a function of temperature for thepolymer blend and composites containing 20wt of PLA
however the composites maintain the plateau 1198641015840 value forabout 10∘C more than the polymer blend Such additionaltemperature resistance before 1198641015840 decay is important foroutdoor thermoplastic applications and indicates that thefiber acts as a reinforcing material due to its rigidity andhydrogen bonding between the polymer blend and the ABFSimilar storage modulus behavior was obtained for the othercomposites Such type of effect has been reported for TPSreinforced with cellulose fibers [22]
The storage modulus at 25∘C of the studied composites isshown in Figure 4 Such figure indicates that higher storagemoduli are obtained with the inclusion of ABF andor PLAand such increase is larger as more PLA andor ABF areadded The reinforcement effect of PLA and ABF along withhydrogen bonding leads to a decrease in chains mobility It
4 International Journal of Polymer Science
6000
5000
4000
3000
2000
1000
0
0 10 20 30
Stor
age m
odul
us (E
998400) (
MPa
)
Poly(lactic acid) content (wt)
ABF content (wt)0
10
15
Figure 4 Storage modulus of polymer blends and composites at25∘C varying PLA content
minus90 minus40 10 60 110 160000
005
010
015
020
025
030
035
040
Temperature (∘C)
tan 120575
ABF content (wt)0
10
15
Figure 5 tan 120575 versus temperature for polymer blend and compos-ites containing 20wt PLA
has been reported that modulus increases with fiber content[7 22 23] due to the high compatibility between TPS andcellulose fillers [5 10] Reports about it include bleachedleaf wood fibers [24] fibers from bleached eucalyptus pulp[25] flax and ramie fibers [26] wood pulp [27] and tunicinwhiskers [28ndash30]
Figure 5 shows tan 120575 versus temperature for the com-posites containing 20wt of PLA This figure shows thatthe peaks appear in three regions (a) around minus55∘C (119879
119892of
glycerol) (b) at 54ndash57∘C which is attributed to 119879119892of PLA
and (c) at 115ndash130∘C that corresponds to 119879119892of S
Table 2 119879119892of starch in polymer blends and composites
PLA content in polymerblend wt
ABF content in composites wt0 10 15
10 120∘C 124∘C 132∘C20 115∘C 120∘C 130∘C30 111∘C 114∘C 127∘C
0 50 100 150 200
Hea
t flow
(Wg
)00
01
02
03
04
05
06
Temperature (∘C)
Fiber content (wt)0
10
15
Figure 6 Thermograms of the polymer blend and compositescontaining 20wt of PLA
Using tan 120575 results of the polymer blend and compositescontaining different amounts of PLA and ABF the 119879
119892values
of TPS are presented in Table 2 The values indicate that anincrease in PLA content promotes a decrease in 119879
119892 such
behavior can be explained by the lower 119879119892value of PLA
compared to that of the starch (119879119892gt 110∘C) [3 4] In Table 2 it
can also be noticed that for constant PLA content there is anincrease in 119879
119892as fiber content increases the 119879
119892displacement
can be attributed to the decrease of starch chainsmobility andthe H-bond interactions between ABF and TPS [7 22 24]
33 Thermal Analysis The DSC thermogram (Figure 6)shows the thermal transitions of the polymer blend andcomposites containing 20wt of PLA For the curves atapproximately 60∘C a change in slope can be observed dueto the 119879
119892of PLA Those temperature values are presented
in Table 3 The small decrement in 119879119892for the composites
with respect to the pure PLA obtained here (62∘C) can beattributed to glycerin migration as Li and Huneault reported[31] In addition Martin and Averous reported a smalldecrease in119879
119892of PLA by the presence of glycerol [32] For the
composites containing the larger amount of fiber (15 wt)the119879119892of PLA shows a slight decrease by enhanced PLA chain
mobility Jaafar et al reported a decrease in 119879119892of PLA which
International Journal of Polymer Science 5
Table 3 119879119892of PLA in polymer blends and composites
PLA content in polymerblend wt
ABF content in composites wt0 10 15
10 570∘C 571∘C 545∘C20 570∘C 573∘C 555∘C30 570∘C 570∘C 560∘C
Table 4 119879119888of PLA in polymer blends and composites
PLA content in polymerblend wt
ABF content in composites wt0 10 15
10 1000∘C 1007∘C 991∘C20 999∘C 998∘C 1010∘C30 989∘C 1004∘C 1002∘C
Table 5 119879119898of PLA in polymer blends and composites
PLA content in polymerblend wt
ABF content in composites wt0 10 15
10 1630∘C 1645∘C 1610∘C20 1659∘C 1636∘C 1634∘C30 1661∘C 1659∘C 1632∘C
they attributed to the inclusion of Kenaf fibers that increasedPLA chains mobility because fibers separate PLA chains [33]
The exothermic peak that appears at approximately 100∘Cis related to PLA crystallization (119879
119888) as a result of the
interaction of PLA and TPS [32] 119879119888values are shown in
Table 4 where no noticeable effect can be seen for a fiber orPLA concentration increase (equivalent to TPS concentrationdecrease) Teixeira et al reported a small decrease in the119879
119888of
PLA using cassava bagasse [14]For the polymeric materials of Figure 6 the small vari-
ation in the slope of the curves indicates that the 119879119892of S
appears at 110ndash130∘C Those values correspond to the tan 120575peaks shown in Figure 5
Figure 6 also shows peaks between 110 and 130∘Cdue to119879119892
of starch which coincide with the 119879119892obtained by mechano-
dynamic tests which confirms that increasing fiber contentincreases 119879
119892
The endothermic peaks at the high temperature zonecorrespond to PLAmelting temperature (119879
119898) The peak tem-
perature values presented in Table 5 show that slight changesin PLA melting temperature correspond to an increase withPLA content and a decreasewithABF addition Such decreasecan be explained by the interference that fibers may cause toallow PLA crystallization Before the PLA melting peaks thecorrespondent small shoulder is attributed to rearrangementof lamellar fractions formed during PLA crystallization [34]or premelting of small crystals
34 Mechanostatical Tests Even though mechanodynamictests allowed the thermomechanical characterization of
Poly(lactic acid) (wt)0 10 20
Youn
g m
odul
us (M
Pa)
0
100
200
300
400
500
600
ABF content (wt)0
10
15
Figure 7 Young modulus of polymer blends and composites at25∘C varying PLA content
Poly(lactic acid) (wt)0 10 20
Flex
ural
mod
ulus
(MPa
)
0
500
1000
1500
2000
2500
3000
3500
ABF content (wt)0
10
15
Figure 8 Flexural modulus of polymer blends and composites at25∘C varying PLA content
extruded materials mechanostatic tests of some of the com-posites are included to confirm their moduli values patternas well as to determine impact resistance behavior In Figure 7Young modulus of polymer blends and composites as afunction of PLA and fiber content is shown The inclusionof PLA andor ABF promotes an increase in modulus Thosepatterns are in agreement with the storage modulus valuesobtained at 25∘C (Figure 4)
Figure 8 shows flexural modulus of the polymeric materi-als as a function of PLA and fiber content For this parameteran increase in PLA andor fiber content leads to composites
6 International Journal of Polymer Science
Poly(lactic acid) content (wt)0 10 20
0
2
4
6
8
10
12
14
16
18Im
pact
resis
tanc
e (kJ
m2)
Fiber content (wt)0
10
15
Figure 9 Impact resistance of polymer blends and composites at25∘C varying PLA content
with higher flexuralmodulus supporting the results obtainedfor the other moduli
In Figure 9 it can be noticed that the increase in rigidityof the TPS caused by the addition of PLA andor ABF leadsto a large decrease in impact resistance
35 Morphology In Figure 10 micrographs of fractured sam-ples of (a) TPS (b) polymer blend containing 20wt of PLAand (c) 80 TPS20 PLA ww with 15 wt ABF composite areshown In Figure 10(a) uniform gelatinized starch granulescan be observed Figure 10(b) shows a stratified brittle surfaceThe fibers in the composite can be seen in Figure 10(c) and arigid fracture is noticed
4 Conclusions
Blends of TPS and PLA and composites of TPSPLAABFprepared by extrusion followed by compressionmoldingwerecharacterized The reinforcing effect of PLA andor ABF inTPS led to an increase in moduli and a decrease in moistureabsorption and impact resistance The TPS glass transitiontemperature increased with ABF content and decreased withPLA content
The reinforcing effect of PLA was enhanced by theincorporation of ABF although the reduction in impactresistance is not convenientThat kind of behavior is expectedgenerically for rigidmaterials nevertheless thewood appear-ance and biodegradability along with the increase in modulias well as thermal resistance and the decrease in waterabsorption justify the production of this type of compositesfor many applications
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
(a)
(b)
(c)
Figure 10 SEM images of polymericmaterials (a) TPS (b) polymerblend containing 20wt PLA and (c) 80 TPS20 PLA ww with15 wt ABF composite
Acknowledgment
F J Aranda-Garcıa acknowledges CONACYT for a scholar-ship
International Journal of Polymer Science 7
References
[1] Institute for Bioplastics and Biocomposites and Nova-InstituteMore Bioplastic Statistic European Bioplastics 2014 httpwwwbio-basedeumarkets
[2] J L Guimaraes F Wypych C K Saul L P Ramos and K GSatyanarayana ldquoStudies of the processing and characterizationof corn starch and its composites with banana and sugarcanefibers from Brazilrdquo Carbohydrate Polymers vol 80 no 1 pp130ndash138 2010
[3] H Wang X Sun and P Seib ldquoEffects of starch moisture onproperties of wheat starchpoly (lactic acid) blend containingmethylenediphenyl diisocyanaterdquo Journal of Polymers and theEnvironment vol 10 no 4 pp 133ndash138 2002
[4] P Sarazin G Li W J Orts and B D Favis ldquoBinary andternary blends of polylactide polycaprolactone and thermo-plastic starchrdquo Polymer vol 49 no 2 pp 599ndash609 2008
[5] A Dufresne and M R Vignon ldquoImprovement of starch filmperformances using cellulosemicrofibrilsrdquoMacromolecules vol31 no 8 pp 2693ndash2696 1998
[6] H Liu F Xie L Yu L Chen and L Li ldquoThermal processing ofstarch-based polymersrdquo Progress in Polymer Science vol 34 no12 pp 1348ndash1368 2009
[7] J Girones J P Lopez P Mutje A J F Carvalho A A SCurvelo and F Vilaseca ldquoNatural fiber-reinforced thermoplas-tic starch composites obtained by melt processingrdquo CompositesScience and Technology vol 72 no 7 pp 858ndash863 2012
[8] R L Shogren ldquoPoly(ethylene oxide)-coated granular starch-poly(hydroxybutyrate-co-hydroxyvalerate) composite materi-alsrdquo Journal of Environmental Polymer Degradation vol 3 no2 pp 75ndash80 1995
[9] L Yu K Dean and L Li ldquoPolymer blends and composites fromrenewable resourcesrdquo Progress in Polymer Science vol 31 no 6pp 576ndash602 2006
[10] A Dufresne D Dupeyre and M R Vignon ldquoCellulosemicrofibrils from potato tuber cells processing and character-ization of starchndashcellulose microfibril compositesrdquo Journal ofApplied Polymer Science vol 76 no 14 pp 2080ndash2092 2000
[11] M J John and S Thomas ldquoBiofibres and biocompositesrdquoCarbohydrate Polymers vol 71 no 3 pp 343ndash364 2008
[12] M A Huneault andH Li ldquoMorphology and properties of com-patibilized polylactidethermoplastic starch blendsrdquo Polymervol 48 no 1 pp 270ndash280 2007
[13] L Jiang B Liu and J Zhang ldquoNovel high-strength thermo-plastic starch reinforced by in situ poly(lactic acid) fibrillationrdquoMacromolecular Materials and Engineering vol 294 no 5 pp301ndash305 2009
[14] E D M Teixeira A A S Curvelo A C Correa J MMarconcini G M Glenn and L H C Mattoso ldquoProperties ofthermoplastic starch from cassava bagasse and cassava starchand their blends with poly (lactic acid)rdquo Industrial Crops andProducts vol 37 no 1 pp 61ndash68 2012
[15] J Castano S Rodrıguez-Llamazares C Carrasco andR BouzaldquoPhysical chemical and mechanical properties of pehuen cellu-losic husk and its pehuen-starch based compositesrdquo Carbohy-drate Polymers vol 90 no 4 pp 1550ndash1556 2012
[16] W Smitthipong R Tantatherdtam and R Chollakup ldquoEffect ofpineapple leaf fiber-reinforced thermoplastic starchpoly(lacticacid) green composite mechanical viscosity and water resis-tance propertiesrdquo Journal ofThermoplastic CompositeMaterialsvol 28 no 5 pp 717ndash729 2015
[17] V A Alvarez and A Vazquez ldquoThermal degradation of cel-lulose derivativesstarch blends and sisal fibre biocompositesrdquoPolymerDegradation and Stability vol 84 no 1 pp 13ndash21 2004
[18] M Prajer and M P Ansell ldquoThermomechanical evaluation ofsisal-PLA compositesrdquo in Proceedings of the 17th InternationalConference on Composite Materials (ICCM rsquo09) pp 27ndash31 July2009
[19] E E M Ahmad and A S Luyt ldquoMorphology thermaland dynamic mechanical properties of poly(lactic acid)sisalwhisker nanocompositesrdquoPolymerComposites vol 33 no 6 pp1025ndash1032 2012
[20] A Campos K B R Teodoro E M Teixeira et al ldquoPropertiesof thermoplastic starch and TPSpolycaprolactone blend rein-forced with sisal whiskers using extrusion processingrdquo PolymerEngineering amp Science vol 53 no 4 pp 800ndash808 2013
[21] M E Vallejos A A S Curvelo EM Teixeira et al ldquoCompositematerials of thermoplastic starch and fibers from the ethanol-water fractionation of bagasserdquo Industrial Crops and Productsvol 33 no 3 pp 739ndash746 2011
[22] L Averous and N Boquillon ldquoBiocomposites based on plas-ticized starch thermal and mechanical behavioursrdquo Carbohy-drate Polymers vol 56 no 2 pp 111ndash122 2004
[23] R Belhassen S Boufi F Vilaseca et al ldquoBiocomposites basedon Alfa fibers and starch-based biopolymerrdquo Polymers forAdvanced Technologies vol 20 no 12 pp 1068ndash1075 2009
[24] L Averous C Fringant and L Moro ldquoPlasticized starch-cellulose interactions in polysaccharide compositesrdquo Polymervol 42 no 15 pp 6565ndash6572 2001
[25] A A S Curvelo A J F De Carvalho and J A M AgnellildquoThermoplastic starch-cellulosic fibers composites preliminaryresultsrdquoCarbohydrate Polymers vol 45 no 2 pp 183ndash188 2001
[26] M Wollerdorfer and H Bader ldquoInfluence of natural fibreson the mechanical properties of biodegradable polymersrdquoIndustrial Crops and Products vol 8 no 2 pp 105ndash112 1998
[27] A J F de Carvalho A A S Curvelo and J A M AgnellildquoWood pulp reinforced thermoplastic starch compositesrdquo Inter-national Journal of Polymeric Materials vol 51 no 7 pp 647ndash660 2002
[28] M N Angles and A Dufresne ldquoPlasticized starchtunieinwhiskers nanocomposites 1 Structural analysisrdquoMacromolecu-les vol 33 no 22 pp 8344ndash8353 2000
[29] M N Angles and A Dufresne ldquoPlasticized starchtunicinwhiskers nanocomposite materials 2 Mechanical behaviorrdquoMacromolecules vol 34 no 9 pp 2921ndash2931 2001
[30] A P Mathew and A Dufresne ldquoMorphological investigationof nanocomposites from sorbitol plasticized starch and tunicinwhiskersrdquo Biomacromolecules vol 3 no 3 pp 609ndash617 2002
[31] H Li andM A Huneault ldquoComparison of sorbitol and glycerolas plasticizers for thermoplastic starch in TPSPLA blendsrdquoJournal of Applied Polymer Science vol 119 no 4 pp 2439ndash24482011
[32] O Martin and L Averous ldquoPoly(lactic acid) plasticization andproperties of biodegradable multiphase systemsrdquo Polymer vol42 no 14 pp 6209ndash6219 2001
[33] W Jaafar W N Raihan S Siti Norasmah et al ldquoThermalproperties of PLAKenaf green nanocomposite effect of chemi-mechanical treatmentrdquo Advanced Materials Research vol 576pp 342ndash344 2012
[34] C Way D Y Wu D Cram K Dean and E Palombo ldquoPro-cessing stability and biodegradation of polylactic Acid (PLA)composites reinforced with cotton linters or maple hardwoodfibresrdquo Journal of Polymers and the Environment vol 21 no 1pp 54ndash70 2013
Submit your manuscripts athttpwwwhindawicom
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CorrosionInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Polymer ScienceInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CeramicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CompositesJournal of
NanoparticlesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Biomaterials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
NanoscienceJournal of
TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of
NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
CrystallographyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CoatingsJournal of
Advances in
Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Smart Materials Research
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MetallurgyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BioMed Research International
MaterialsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nano
materials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofNanomaterials
International Journal of Polymer Science 3
Time (days)0 5 10 15 20 25
Wat
er ab
sorp
tion
(wt
)
0
3
6
9
12
15
Fiber content (wt)0
10
15
Figure 1 Moisture absorption of TPSPLAFiber composites as afunction of time for the polymer blend and composites containing20wt PLA
Instruments) using ASTM D3418-03 Heating rate was10∘Cmin from 20 to 180∘C
25 Morphology Samples were observed by Field EmissionScanning Electronic Microscopy (FE-SEM (Tescan Mira3))The samples were frozen in liquid nitrogen for 5 minutesbefore fracture Subsequently the samples were dried at 60∘Cbefore FE-SEM observation
3 Results
31 Moisture Absorption Figure 1 shows moisture absorp-tion of the polymer blend and the composites containing20wt PLA Such figure illustrates that the rate of moistureabsorption decreases as the ABF content increases and thatequilibrium is reached in approximately two weeks Similarmoisture absorption behavior was obtained for the othermaterials
For moisture absorption it can also be noticed that anincrease in ABF content reduces the equilibrium moisturevalue (Figure 2) that behavior can be explained in terms ofthe lower hydrophilic character of the fiber comparing withtheTPS Like in this case it has been reported that compositesof TPS with sugarcane bagasse fibers showed a decreasein moisture equilibrium when fiber content was increased[21] Additionally since PLA is a less hydrophilic polymerthan TPS independently of fiber content increasing PLAconcentration causes a decrease in the moisture absorptioncapacity of the composite (Figure 2)
32 Thermomechanical Analysis In Figure 3 the storagemodulus (1198641015840) is presented as a function of temperature for thecomposites containing 20wt of PLAThere an overlappingplateau for the 3 samples can be observed from minus30 to 40∘C
Poly(lactic acid) content (wt)0 10 20 30
Wat
er ab
sorp
tion
(wt
)
0
2
4
6
8
10
ABF content (wt)0
10
15
Figure 2 Equilibrium moisture of polymer blends and compositesvarying PLA content
Stor
age m
odul
us (E
998400) (
MPa
)
1e + 5
1e + 4
1e + 3
1e + 2
1e + 1
minus90 minus40 10 60 110 160
Temperature (∘C)
ABF content (wt)0
10
15
Figure 3 Storage modulus as a function of temperature for thepolymer blend and composites containing 20wt of PLA
however the composites maintain the plateau 1198641015840 value forabout 10∘C more than the polymer blend Such additionaltemperature resistance before 1198641015840 decay is important foroutdoor thermoplastic applications and indicates that thefiber acts as a reinforcing material due to its rigidity andhydrogen bonding between the polymer blend and the ABFSimilar storage modulus behavior was obtained for the othercomposites Such type of effect has been reported for TPSreinforced with cellulose fibers [22]
The storage modulus at 25∘C of the studied composites isshown in Figure 4 Such figure indicates that higher storagemoduli are obtained with the inclusion of ABF andor PLAand such increase is larger as more PLA andor ABF areadded The reinforcement effect of PLA and ABF along withhydrogen bonding leads to a decrease in chains mobility It
4 International Journal of Polymer Science
6000
5000
4000
3000
2000
1000
0
0 10 20 30
Stor
age m
odul
us (E
998400) (
MPa
)
Poly(lactic acid) content (wt)
ABF content (wt)0
10
15
Figure 4 Storage modulus of polymer blends and composites at25∘C varying PLA content
minus90 minus40 10 60 110 160000
005
010
015
020
025
030
035
040
Temperature (∘C)
tan 120575
ABF content (wt)0
10
15
Figure 5 tan 120575 versus temperature for polymer blend and compos-ites containing 20wt PLA
has been reported that modulus increases with fiber content[7 22 23] due to the high compatibility between TPS andcellulose fillers [5 10] Reports about it include bleachedleaf wood fibers [24] fibers from bleached eucalyptus pulp[25] flax and ramie fibers [26] wood pulp [27] and tunicinwhiskers [28ndash30]
Figure 5 shows tan 120575 versus temperature for the com-posites containing 20wt of PLA This figure shows thatthe peaks appear in three regions (a) around minus55∘C (119879
119892of
glycerol) (b) at 54ndash57∘C which is attributed to 119879119892of PLA
and (c) at 115ndash130∘C that corresponds to 119879119892of S
Table 2 119879119892of starch in polymer blends and composites
PLA content in polymerblend wt
ABF content in composites wt0 10 15
10 120∘C 124∘C 132∘C20 115∘C 120∘C 130∘C30 111∘C 114∘C 127∘C
0 50 100 150 200
Hea
t flow
(Wg
)00
01
02
03
04
05
06
Temperature (∘C)
Fiber content (wt)0
10
15
Figure 6 Thermograms of the polymer blend and compositescontaining 20wt of PLA
Using tan 120575 results of the polymer blend and compositescontaining different amounts of PLA and ABF the 119879
119892values
of TPS are presented in Table 2 The values indicate that anincrease in PLA content promotes a decrease in 119879
119892 such
behavior can be explained by the lower 119879119892value of PLA
compared to that of the starch (119879119892gt 110∘C) [3 4] In Table 2 it
can also be noticed that for constant PLA content there is anincrease in 119879
119892as fiber content increases the 119879
119892displacement
can be attributed to the decrease of starch chainsmobility andthe H-bond interactions between ABF and TPS [7 22 24]
33 Thermal Analysis The DSC thermogram (Figure 6)shows the thermal transitions of the polymer blend andcomposites containing 20wt of PLA For the curves atapproximately 60∘C a change in slope can be observed dueto the 119879
119892of PLA Those temperature values are presented
in Table 3 The small decrement in 119879119892for the composites
with respect to the pure PLA obtained here (62∘C) can beattributed to glycerin migration as Li and Huneault reported[31] In addition Martin and Averous reported a smalldecrease in119879
119892of PLA by the presence of glycerol [32] For the
composites containing the larger amount of fiber (15 wt)the119879119892of PLA shows a slight decrease by enhanced PLA chain
mobility Jaafar et al reported a decrease in 119879119892of PLA which
International Journal of Polymer Science 5
Table 3 119879119892of PLA in polymer blends and composites
PLA content in polymerblend wt
ABF content in composites wt0 10 15
10 570∘C 571∘C 545∘C20 570∘C 573∘C 555∘C30 570∘C 570∘C 560∘C
Table 4 119879119888of PLA in polymer blends and composites
PLA content in polymerblend wt
ABF content in composites wt0 10 15
10 1000∘C 1007∘C 991∘C20 999∘C 998∘C 1010∘C30 989∘C 1004∘C 1002∘C
Table 5 119879119898of PLA in polymer blends and composites
PLA content in polymerblend wt
ABF content in composites wt0 10 15
10 1630∘C 1645∘C 1610∘C20 1659∘C 1636∘C 1634∘C30 1661∘C 1659∘C 1632∘C
they attributed to the inclusion of Kenaf fibers that increasedPLA chains mobility because fibers separate PLA chains [33]
The exothermic peak that appears at approximately 100∘Cis related to PLA crystallization (119879
119888) as a result of the
interaction of PLA and TPS [32] 119879119888values are shown in
Table 4 where no noticeable effect can be seen for a fiber orPLA concentration increase (equivalent to TPS concentrationdecrease) Teixeira et al reported a small decrease in the119879
119888of
PLA using cassava bagasse [14]For the polymeric materials of Figure 6 the small vari-
ation in the slope of the curves indicates that the 119879119892of S
appears at 110ndash130∘C Those values correspond to the tan 120575peaks shown in Figure 5
Figure 6 also shows peaks between 110 and 130∘Cdue to119879119892
of starch which coincide with the 119879119892obtained by mechano-
dynamic tests which confirms that increasing fiber contentincreases 119879
119892
The endothermic peaks at the high temperature zonecorrespond to PLAmelting temperature (119879
119898) The peak tem-
perature values presented in Table 5 show that slight changesin PLA melting temperature correspond to an increase withPLA content and a decreasewithABF addition Such decreasecan be explained by the interference that fibers may cause toallow PLA crystallization Before the PLA melting peaks thecorrespondent small shoulder is attributed to rearrangementof lamellar fractions formed during PLA crystallization [34]or premelting of small crystals
34 Mechanostatical Tests Even though mechanodynamictests allowed the thermomechanical characterization of
Poly(lactic acid) (wt)0 10 20
Youn
g m
odul
us (M
Pa)
0
100
200
300
400
500
600
ABF content (wt)0
10
15
Figure 7 Young modulus of polymer blends and composites at25∘C varying PLA content
Poly(lactic acid) (wt)0 10 20
Flex
ural
mod
ulus
(MPa
)
0
500
1000
1500
2000
2500
3000
3500
ABF content (wt)0
10
15
Figure 8 Flexural modulus of polymer blends and composites at25∘C varying PLA content
extruded materials mechanostatic tests of some of the com-posites are included to confirm their moduli values patternas well as to determine impact resistance behavior In Figure 7Young modulus of polymer blends and composites as afunction of PLA and fiber content is shown The inclusionof PLA andor ABF promotes an increase in modulus Thosepatterns are in agreement with the storage modulus valuesobtained at 25∘C (Figure 4)
Figure 8 shows flexural modulus of the polymeric materi-als as a function of PLA and fiber content For this parameteran increase in PLA andor fiber content leads to composites
6 International Journal of Polymer Science
Poly(lactic acid) content (wt)0 10 20
0
2
4
6
8
10
12
14
16
18Im
pact
resis
tanc
e (kJ
m2)
Fiber content (wt)0
10
15
Figure 9 Impact resistance of polymer blends and composites at25∘C varying PLA content
with higher flexuralmodulus supporting the results obtainedfor the other moduli
In Figure 9 it can be noticed that the increase in rigidityof the TPS caused by the addition of PLA andor ABF leadsto a large decrease in impact resistance
35 Morphology In Figure 10 micrographs of fractured sam-ples of (a) TPS (b) polymer blend containing 20wt of PLAand (c) 80 TPS20 PLA ww with 15 wt ABF composite areshown In Figure 10(a) uniform gelatinized starch granulescan be observed Figure 10(b) shows a stratified brittle surfaceThe fibers in the composite can be seen in Figure 10(c) and arigid fracture is noticed
4 Conclusions
Blends of TPS and PLA and composites of TPSPLAABFprepared by extrusion followed by compressionmoldingwerecharacterized The reinforcing effect of PLA andor ABF inTPS led to an increase in moduli and a decrease in moistureabsorption and impact resistance The TPS glass transitiontemperature increased with ABF content and decreased withPLA content
The reinforcing effect of PLA was enhanced by theincorporation of ABF although the reduction in impactresistance is not convenientThat kind of behavior is expectedgenerically for rigidmaterials nevertheless thewood appear-ance and biodegradability along with the increase in modulias well as thermal resistance and the decrease in waterabsorption justify the production of this type of compositesfor many applications
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
(a)
(b)
(c)
Figure 10 SEM images of polymericmaterials (a) TPS (b) polymerblend containing 20wt PLA and (c) 80 TPS20 PLA ww with15 wt ABF composite
Acknowledgment
F J Aranda-Garcıa acknowledges CONACYT for a scholar-ship
International Journal of Polymer Science 7
References
[1] Institute for Bioplastics and Biocomposites and Nova-InstituteMore Bioplastic Statistic European Bioplastics 2014 httpwwwbio-basedeumarkets
[2] J L Guimaraes F Wypych C K Saul L P Ramos and K GSatyanarayana ldquoStudies of the processing and characterizationof corn starch and its composites with banana and sugarcanefibers from Brazilrdquo Carbohydrate Polymers vol 80 no 1 pp130ndash138 2010
[3] H Wang X Sun and P Seib ldquoEffects of starch moisture onproperties of wheat starchpoly (lactic acid) blend containingmethylenediphenyl diisocyanaterdquo Journal of Polymers and theEnvironment vol 10 no 4 pp 133ndash138 2002
[4] P Sarazin G Li W J Orts and B D Favis ldquoBinary andternary blends of polylactide polycaprolactone and thermo-plastic starchrdquo Polymer vol 49 no 2 pp 599ndash609 2008
[5] A Dufresne and M R Vignon ldquoImprovement of starch filmperformances using cellulosemicrofibrilsrdquoMacromolecules vol31 no 8 pp 2693ndash2696 1998
[6] H Liu F Xie L Yu L Chen and L Li ldquoThermal processing ofstarch-based polymersrdquo Progress in Polymer Science vol 34 no12 pp 1348ndash1368 2009
[7] J Girones J P Lopez P Mutje A J F Carvalho A A SCurvelo and F Vilaseca ldquoNatural fiber-reinforced thermoplas-tic starch composites obtained by melt processingrdquo CompositesScience and Technology vol 72 no 7 pp 858ndash863 2012
[8] R L Shogren ldquoPoly(ethylene oxide)-coated granular starch-poly(hydroxybutyrate-co-hydroxyvalerate) composite materi-alsrdquo Journal of Environmental Polymer Degradation vol 3 no2 pp 75ndash80 1995
[9] L Yu K Dean and L Li ldquoPolymer blends and composites fromrenewable resourcesrdquo Progress in Polymer Science vol 31 no 6pp 576ndash602 2006
[10] A Dufresne D Dupeyre and M R Vignon ldquoCellulosemicrofibrils from potato tuber cells processing and character-ization of starchndashcellulose microfibril compositesrdquo Journal ofApplied Polymer Science vol 76 no 14 pp 2080ndash2092 2000
[11] M J John and S Thomas ldquoBiofibres and biocompositesrdquoCarbohydrate Polymers vol 71 no 3 pp 343ndash364 2008
[12] M A Huneault andH Li ldquoMorphology and properties of com-patibilized polylactidethermoplastic starch blendsrdquo Polymervol 48 no 1 pp 270ndash280 2007
[13] L Jiang B Liu and J Zhang ldquoNovel high-strength thermo-plastic starch reinforced by in situ poly(lactic acid) fibrillationrdquoMacromolecular Materials and Engineering vol 294 no 5 pp301ndash305 2009
[14] E D M Teixeira A A S Curvelo A C Correa J MMarconcini G M Glenn and L H C Mattoso ldquoProperties ofthermoplastic starch from cassava bagasse and cassava starchand their blends with poly (lactic acid)rdquo Industrial Crops andProducts vol 37 no 1 pp 61ndash68 2012
[15] J Castano S Rodrıguez-Llamazares C Carrasco andR BouzaldquoPhysical chemical and mechanical properties of pehuen cellu-losic husk and its pehuen-starch based compositesrdquo Carbohy-drate Polymers vol 90 no 4 pp 1550ndash1556 2012
[16] W Smitthipong R Tantatherdtam and R Chollakup ldquoEffect ofpineapple leaf fiber-reinforced thermoplastic starchpoly(lacticacid) green composite mechanical viscosity and water resis-tance propertiesrdquo Journal ofThermoplastic CompositeMaterialsvol 28 no 5 pp 717ndash729 2015
[17] V A Alvarez and A Vazquez ldquoThermal degradation of cel-lulose derivativesstarch blends and sisal fibre biocompositesrdquoPolymerDegradation and Stability vol 84 no 1 pp 13ndash21 2004
[18] M Prajer and M P Ansell ldquoThermomechanical evaluation ofsisal-PLA compositesrdquo in Proceedings of the 17th InternationalConference on Composite Materials (ICCM rsquo09) pp 27ndash31 July2009
[19] E E M Ahmad and A S Luyt ldquoMorphology thermaland dynamic mechanical properties of poly(lactic acid)sisalwhisker nanocompositesrdquoPolymerComposites vol 33 no 6 pp1025ndash1032 2012
[20] A Campos K B R Teodoro E M Teixeira et al ldquoPropertiesof thermoplastic starch and TPSpolycaprolactone blend rein-forced with sisal whiskers using extrusion processingrdquo PolymerEngineering amp Science vol 53 no 4 pp 800ndash808 2013
[21] M E Vallejos A A S Curvelo EM Teixeira et al ldquoCompositematerials of thermoplastic starch and fibers from the ethanol-water fractionation of bagasserdquo Industrial Crops and Productsvol 33 no 3 pp 739ndash746 2011
[22] L Averous and N Boquillon ldquoBiocomposites based on plas-ticized starch thermal and mechanical behavioursrdquo Carbohy-drate Polymers vol 56 no 2 pp 111ndash122 2004
[23] R Belhassen S Boufi F Vilaseca et al ldquoBiocomposites basedon Alfa fibers and starch-based biopolymerrdquo Polymers forAdvanced Technologies vol 20 no 12 pp 1068ndash1075 2009
[24] L Averous C Fringant and L Moro ldquoPlasticized starch-cellulose interactions in polysaccharide compositesrdquo Polymervol 42 no 15 pp 6565ndash6572 2001
[25] A A S Curvelo A J F De Carvalho and J A M AgnellildquoThermoplastic starch-cellulosic fibers composites preliminaryresultsrdquoCarbohydrate Polymers vol 45 no 2 pp 183ndash188 2001
[26] M Wollerdorfer and H Bader ldquoInfluence of natural fibreson the mechanical properties of biodegradable polymersrdquoIndustrial Crops and Products vol 8 no 2 pp 105ndash112 1998
[27] A J F de Carvalho A A S Curvelo and J A M AgnellildquoWood pulp reinforced thermoplastic starch compositesrdquo Inter-national Journal of Polymeric Materials vol 51 no 7 pp 647ndash660 2002
[28] M N Angles and A Dufresne ldquoPlasticized starchtunieinwhiskers nanocomposites 1 Structural analysisrdquoMacromolecu-les vol 33 no 22 pp 8344ndash8353 2000
[29] M N Angles and A Dufresne ldquoPlasticized starchtunicinwhiskers nanocomposite materials 2 Mechanical behaviorrdquoMacromolecules vol 34 no 9 pp 2921ndash2931 2001
[30] A P Mathew and A Dufresne ldquoMorphological investigationof nanocomposites from sorbitol plasticized starch and tunicinwhiskersrdquo Biomacromolecules vol 3 no 3 pp 609ndash617 2002
[31] H Li andM A Huneault ldquoComparison of sorbitol and glycerolas plasticizers for thermoplastic starch in TPSPLA blendsrdquoJournal of Applied Polymer Science vol 119 no 4 pp 2439ndash24482011
[32] O Martin and L Averous ldquoPoly(lactic acid) plasticization andproperties of biodegradable multiphase systemsrdquo Polymer vol42 no 14 pp 6209ndash6219 2001
[33] W Jaafar W N Raihan S Siti Norasmah et al ldquoThermalproperties of PLAKenaf green nanocomposite effect of chemi-mechanical treatmentrdquo Advanced Materials Research vol 576pp 342ndash344 2012
[34] C Way D Y Wu D Cram K Dean and E Palombo ldquoPro-cessing stability and biodegradation of polylactic Acid (PLA)composites reinforced with cotton linters or maple hardwoodfibresrdquo Journal of Polymers and the Environment vol 21 no 1pp 54ndash70 2013
Submit your manuscripts athttpwwwhindawicom
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CorrosionInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Polymer ScienceInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CeramicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CompositesJournal of
NanoparticlesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Biomaterials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
NanoscienceJournal of
TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of
NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
CrystallographyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CoatingsJournal of
Advances in
Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Smart Materials Research
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MetallurgyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BioMed Research International
MaterialsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nano
materials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofNanomaterials
4 International Journal of Polymer Science
6000
5000
4000
3000
2000
1000
0
0 10 20 30
Stor
age m
odul
us (E
998400) (
MPa
)
Poly(lactic acid) content (wt)
ABF content (wt)0
10
15
Figure 4 Storage modulus of polymer blends and composites at25∘C varying PLA content
minus90 minus40 10 60 110 160000
005
010
015
020
025
030
035
040
Temperature (∘C)
tan 120575
ABF content (wt)0
10
15
Figure 5 tan 120575 versus temperature for polymer blend and compos-ites containing 20wt PLA
has been reported that modulus increases with fiber content[7 22 23] due to the high compatibility between TPS andcellulose fillers [5 10] Reports about it include bleachedleaf wood fibers [24] fibers from bleached eucalyptus pulp[25] flax and ramie fibers [26] wood pulp [27] and tunicinwhiskers [28ndash30]
Figure 5 shows tan 120575 versus temperature for the com-posites containing 20wt of PLA This figure shows thatthe peaks appear in three regions (a) around minus55∘C (119879
119892of
glycerol) (b) at 54ndash57∘C which is attributed to 119879119892of PLA
and (c) at 115ndash130∘C that corresponds to 119879119892of S
Table 2 119879119892of starch in polymer blends and composites
PLA content in polymerblend wt
ABF content in composites wt0 10 15
10 120∘C 124∘C 132∘C20 115∘C 120∘C 130∘C30 111∘C 114∘C 127∘C
0 50 100 150 200
Hea
t flow
(Wg
)00
01
02
03
04
05
06
Temperature (∘C)
Fiber content (wt)0
10
15
Figure 6 Thermograms of the polymer blend and compositescontaining 20wt of PLA
Using tan 120575 results of the polymer blend and compositescontaining different amounts of PLA and ABF the 119879
119892values
of TPS are presented in Table 2 The values indicate that anincrease in PLA content promotes a decrease in 119879
119892 such
behavior can be explained by the lower 119879119892value of PLA
compared to that of the starch (119879119892gt 110∘C) [3 4] In Table 2 it
can also be noticed that for constant PLA content there is anincrease in 119879
119892as fiber content increases the 119879
119892displacement
can be attributed to the decrease of starch chainsmobility andthe H-bond interactions between ABF and TPS [7 22 24]
33 Thermal Analysis The DSC thermogram (Figure 6)shows the thermal transitions of the polymer blend andcomposites containing 20wt of PLA For the curves atapproximately 60∘C a change in slope can be observed dueto the 119879
119892of PLA Those temperature values are presented
in Table 3 The small decrement in 119879119892for the composites
with respect to the pure PLA obtained here (62∘C) can beattributed to glycerin migration as Li and Huneault reported[31] In addition Martin and Averous reported a smalldecrease in119879
119892of PLA by the presence of glycerol [32] For the
composites containing the larger amount of fiber (15 wt)the119879119892of PLA shows a slight decrease by enhanced PLA chain
mobility Jaafar et al reported a decrease in 119879119892of PLA which
International Journal of Polymer Science 5
Table 3 119879119892of PLA in polymer blends and composites
PLA content in polymerblend wt
ABF content in composites wt0 10 15
10 570∘C 571∘C 545∘C20 570∘C 573∘C 555∘C30 570∘C 570∘C 560∘C
Table 4 119879119888of PLA in polymer blends and composites
PLA content in polymerblend wt
ABF content in composites wt0 10 15
10 1000∘C 1007∘C 991∘C20 999∘C 998∘C 1010∘C30 989∘C 1004∘C 1002∘C
Table 5 119879119898of PLA in polymer blends and composites
PLA content in polymerblend wt
ABF content in composites wt0 10 15
10 1630∘C 1645∘C 1610∘C20 1659∘C 1636∘C 1634∘C30 1661∘C 1659∘C 1632∘C
they attributed to the inclusion of Kenaf fibers that increasedPLA chains mobility because fibers separate PLA chains [33]
The exothermic peak that appears at approximately 100∘Cis related to PLA crystallization (119879
119888) as a result of the
interaction of PLA and TPS [32] 119879119888values are shown in
Table 4 where no noticeable effect can be seen for a fiber orPLA concentration increase (equivalent to TPS concentrationdecrease) Teixeira et al reported a small decrease in the119879
119888of
PLA using cassava bagasse [14]For the polymeric materials of Figure 6 the small vari-
ation in the slope of the curves indicates that the 119879119892of S
appears at 110ndash130∘C Those values correspond to the tan 120575peaks shown in Figure 5
Figure 6 also shows peaks between 110 and 130∘Cdue to119879119892
of starch which coincide with the 119879119892obtained by mechano-
dynamic tests which confirms that increasing fiber contentincreases 119879
119892
The endothermic peaks at the high temperature zonecorrespond to PLAmelting temperature (119879
119898) The peak tem-
perature values presented in Table 5 show that slight changesin PLA melting temperature correspond to an increase withPLA content and a decreasewithABF addition Such decreasecan be explained by the interference that fibers may cause toallow PLA crystallization Before the PLA melting peaks thecorrespondent small shoulder is attributed to rearrangementof lamellar fractions formed during PLA crystallization [34]or premelting of small crystals
34 Mechanostatical Tests Even though mechanodynamictests allowed the thermomechanical characterization of
Poly(lactic acid) (wt)0 10 20
Youn
g m
odul
us (M
Pa)
0
100
200
300
400
500
600
ABF content (wt)0
10
15
Figure 7 Young modulus of polymer blends and composites at25∘C varying PLA content
Poly(lactic acid) (wt)0 10 20
Flex
ural
mod
ulus
(MPa
)
0
500
1000
1500
2000
2500
3000
3500
ABF content (wt)0
10
15
Figure 8 Flexural modulus of polymer blends and composites at25∘C varying PLA content
extruded materials mechanostatic tests of some of the com-posites are included to confirm their moduli values patternas well as to determine impact resistance behavior In Figure 7Young modulus of polymer blends and composites as afunction of PLA and fiber content is shown The inclusionof PLA andor ABF promotes an increase in modulus Thosepatterns are in agreement with the storage modulus valuesobtained at 25∘C (Figure 4)
Figure 8 shows flexural modulus of the polymeric materi-als as a function of PLA and fiber content For this parameteran increase in PLA andor fiber content leads to composites
6 International Journal of Polymer Science
Poly(lactic acid) content (wt)0 10 20
0
2
4
6
8
10
12
14
16
18Im
pact
resis
tanc
e (kJ
m2)
Fiber content (wt)0
10
15
Figure 9 Impact resistance of polymer blends and composites at25∘C varying PLA content
with higher flexuralmodulus supporting the results obtainedfor the other moduli
In Figure 9 it can be noticed that the increase in rigidityof the TPS caused by the addition of PLA andor ABF leadsto a large decrease in impact resistance
35 Morphology In Figure 10 micrographs of fractured sam-ples of (a) TPS (b) polymer blend containing 20wt of PLAand (c) 80 TPS20 PLA ww with 15 wt ABF composite areshown In Figure 10(a) uniform gelatinized starch granulescan be observed Figure 10(b) shows a stratified brittle surfaceThe fibers in the composite can be seen in Figure 10(c) and arigid fracture is noticed
4 Conclusions
Blends of TPS and PLA and composites of TPSPLAABFprepared by extrusion followed by compressionmoldingwerecharacterized The reinforcing effect of PLA andor ABF inTPS led to an increase in moduli and a decrease in moistureabsorption and impact resistance The TPS glass transitiontemperature increased with ABF content and decreased withPLA content
The reinforcing effect of PLA was enhanced by theincorporation of ABF although the reduction in impactresistance is not convenientThat kind of behavior is expectedgenerically for rigidmaterials nevertheless thewood appear-ance and biodegradability along with the increase in modulias well as thermal resistance and the decrease in waterabsorption justify the production of this type of compositesfor many applications
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
(a)
(b)
(c)
Figure 10 SEM images of polymericmaterials (a) TPS (b) polymerblend containing 20wt PLA and (c) 80 TPS20 PLA ww with15 wt ABF composite
Acknowledgment
F J Aranda-Garcıa acknowledges CONACYT for a scholar-ship
International Journal of Polymer Science 7
References
[1] Institute for Bioplastics and Biocomposites and Nova-InstituteMore Bioplastic Statistic European Bioplastics 2014 httpwwwbio-basedeumarkets
[2] J L Guimaraes F Wypych C K Saul L P Ramos and K GSatyanarayana ldquoStudies of the processing and characterizationof corn starch and its composites with banana and sugarcanefibers from Brazilrdquo Carbohydrate Polymers vol 80 no 1 pp130ndash138 2010
[3] H Wang X Sun and P Seib ldquoEffects of starch moisture onproperties of wheat starchpoly (lactic acid) blend containingmethylenediphenyl diisocyanaterdquo Journal of Polymers and theEnvironment vol 10 no 4 pp 133ndash138 2002
[4] P Sarazin G Li W J Orts and B D Favis ldquoBinary andternary blends of polylactide polycaprolactone and thermo-plastic starchrdquo Polymer vol 49 no 2 pp 599ndash609 2008
[5] A Dufresne and M R Vignon ldquoImprovement of starch filmperformances using cellulosemicrofibrilsrdquoMacromolecules vol31 no 8 pp 2693ndash2696 1998
[6] H Liu F Xie L Yu L Chen and L Li ldquoThermal processing ofstarch-based polymersrdquo Progress in Polymer Science vol 34 no12 pp 1348ndash1368 2009
[7] J Girones J P Lopez P Mutje A J F Carvalho A A SCurvelo and F Vilaseca ldquoNatural fiber-reinforced thermoplas-tic starch composites obtained by melt processingrdquo CompositesScience and Technology vol 72 no 7 pp 858ndash863 2012
[8] R L Shogren ldquoPoly(ethylene oxide)-coated granular starch-poly(hydroxybutyrate-co-hydroxyvalerate) composite materi-alsrdquo Journal of Environmental Polymer Degradation vol 3 no2 pp 75ndash80 1995
[9] L Yu K Dean and L Li ldquoPolymer blends and composites fromrenewable resourcesrdquo Progress in Polymer Science vol 31 no 6pp 576ndash602 2006
[10] A Dufresne D Dupeyre and M R Vignon ldquoCellulosemicrofibrils from potato tuber cells processing and character-ization of starchndashcellulose microfibril compositesrdquo Journal ofApplied Polymer Science vol 76 no 14 pp 2080ndash2092 2000
[11] M J John and S Thomas ldquoBiofibres and biocompositesrdquoCarbohydrate Polymers vol 71 no 3 pp 343ndash364 2008
[12] M A Huneault andH Li ldquoMorphology and properties of com-patibilized polylactidethermoplastic starch blendsrdquo Polymervol 48 no 1 pp 270ndash280 2007
[13] L Jiang B Liu and J Zhang ldquoNovel high-strength thermo-plastic starch reinforced by in situ poly(lactic acid) fibrillationrdquoMacromolecular Materials and Engineering vol 294 no 5 pp301ndash305 2009
[14] E D M Teixeira A A S Curvelo A C Correa J MMarconcini G M Glenn and L H C Mattoso ldquoProperties ofthermoplastic starch from cassava bagasse and cassava starchand their blends with poly (lactic acid)rdquo Industrial Crops andProducts vol 37 no 1 pp 61ndash68 2012
[15] J Castano S Rodrıguez-Llamazares C Carrasco andR BouzaldquoPhysical chemical and mechanical properties of pehuen cellu-losic husk and its pehuen-starch based compositesrdquo Carbohy-drate Polymers vol 90 no 4 pp 1550ndash1556 2012
[16] W Smitthipong R Tantatherdtam and R Chollakup ldquoEffect ofpineapple leaf fiber-reinforced thermoplastic starchpoly(lacticacid) green composite mechanical viscosity and water resis-tance propertiesrdquo Journal ofThermoplastic CompositeMaterialsvol 28 no 5 pp 717ndash729 2015
[17] V A Alvarez and A Vazquez ldquoThermal degradation of cel-lulose derivativesstarch blends and sisal fibre biocompositesrdquoPolymerDegradation and Stability vol 84 no 1 pp 13ndash21 2004
[18] M Prajer and M P Ansell ldquoThermomechanical evaluation ofsisal-PLA compositesrdquo in Proceedings of the 17th InternationalConference on Composite Materials (ICCM rsquo09) pp 27ndash31 July2009
[19] E E M Ahmad and A S Luyt ldquoMorphology thermaland dynamic mechanical properties of poly(lactic acid)sisalwhisker nanocompositesrdquoPolymerComposites vol 33 no 6 pp1025ndash1032 2012
[20] A Campos K B R Teodoro E M Teixeira et al ldquoPropertiesof thermoplastic starch and TPSpolycaprolactone blend rein-forced with sisal whiskers using extrusion processingrdquo PolymerEngineering amp Science vol 53 no 4 pp 800ndash808 2013
[21] M E Vallejos A A S Curvelo EM Teixeira et al ldquoCompositematerials of thermoplastic starch and fibers from the ethanol-water fractionation of bagasserdquo Industrial Crops and Productsvol 33 no 3 pp 739ndash746 2011
[22] L Averous and N Boquillon ldquoBiocomposites based on plas-ticized starch thermal and mechanical behavioursrdquo Carbohy-drate Polymers vol 56 no 2 pp 111ndash122 2004
[23] R Belhassen S Boufi F Vilaseca et al ldquoBiocomposites basedon Alfa fibers and starch-based biopolymerrdquo Polymers forAdvanced Technologies vol 20 no 12 pp 1068ndash1075 2009
[24] L Averous C Fringant and L Moro ldquoPlasticized starch-cellulose interactions in polysaccharide compositesrdquo Polymervol 42 no 15 pp 6565ndash6572 2001
[25] A A S Curvelo A J F De Carvalho and J A M AgnellildquoThermoplastic starch-cellulosic fibers composites preliminaryresultsrdquoCarbohydrate Polymers vol 45 no 2 pp 183ndash188 2001
[26] M Wollerdorfer and H Bader ldquoInfluence of natural fibreson the mechanical properties of biodegradable polymersrdquoIndustrial Crops and Products vol 8 no 2 pp 105ndash112 1998
[27] A J F de Carvalho A A S Curvelo and J A M AgnellildquoWood pulp reinforced thermoplastic starch compositesrdquo Inter-national Journal of Polymeric Materials vol 51 no 7 pp 647ndash660 2002
[28] M N Angles and A Dufresne ldquoPlasticized starchtunieinwhiskers nanocomposites 1 Structural analysisrdquoMacromolecu-les vol 33 no 22 pp 8344ndash8353 2000
[29] M N Angles and A Dufresne ldquoPlasticized starchtunicinwhiskers nanocomposite materials 2 Mechanical behaviorrdquoMacromolecules vol 34 no 9 pp 2921ndash2931 2001
[30] A P Mathew and A Dufresne ldquoMorphological investigationof nanocomposites from sorbitol plasticized starch and tunicinwhiskersrdquo Biomacromolecules vol 3 no 3 pp 609ndash617 2002
[31] H Li andM A Huneault ldquoComparison of sorbitol and glycerolas plasticizers for thermoplastic starch in TPSPLA blendsrdquoJournal of Applied Polymer Science vol 119 no 4 pp 2439ndash24482011
[32] O Martin and L Averous ldquoPoly(lactic acid) plasticization andproperties of biodegradable multiphase systemsrdquo Polymer vol42 no 14 pp 6209ndash6219 2001
[33] W Jaafar W N Raihan S Siti Norasmah et al ldquoThermalproperties of PLAKenaf green nanocomposite effect of chemi-mechanical treatmentrdquo Advanced Materials Research vol 576pp 342ndash344 2012
[34] C Way D Y Wu D Cram K Dean and E Palombo ldquoPro-cessing stability and biodegradation of polylactic Acid (PLA)composites reinforced with cotton linters or maple hardwoodfibresrdquo Journal of Polymers and the Environment vol 21 no 1pp 54ndash70 2013
Submit your manuscripts athttpwwwhindawicom
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CorrosionInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Polymer ScienceInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CeramicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CompositesJournal of
NanoparticlesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Biomaterials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
NanoscienceJournal of
TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of
NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
CrystallographyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CoatingsJournal of
Advances in
Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Smart Materials Research
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MetallurgyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BioMed Research International
MaterialsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nano
materials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofNanomaterials
International Journal of Polymer Science 5
Table 3 119879119892of PLA in polymer blends and composites
PLA content in polymerblend wt
ABF content in composites wt0 10 15
10 570∘C 571∘C 545∘C20 570∘C 573∘C 555∘C30 570∘C 570∘C 560∘C
Table 4 119879119888of PLA in polymer blends and composites
PLA content in polymerblend wt
ABF content in composites wt0 10 15
10 1000∘C 1007∘C 991∘C20 999∘C 998∘C 1010∘C30 989∘C 1004∘C 1002∘C
Table 5 119879119898of PLA in polymer blends and composites
PLA content in polymerblend wt
ABF content in composites wt0 10 15
10 1630∘C 1645∘C 1610∘C20 1659∘C 1636∘C 1634∘C30 1661∘C 1659∘C 1632∘C
they attributed to the inclusion of Kenaf fibers that increasedPLA chains mobility because fibers separate PLA chains [33]
The exothermic peak that appears at approximately 100∘Cis related to PLA crystallization (119879
119888) as a result of the
interaction of PLA and TPS [32] 119879119888values are shown in
Table 4 where no noticeable effect can be seen for a fiber orPLA concentration increase (equivalent to TPS concentrationdecrease) Teixeira et al reported a small decrease in the119879
119888of
PLA using cassava bagasse [14]For the polymeric materials of Figure 6 the small vari-
ation in the slope of the curves indicates that the 119879119892of S
appears at 110ndash130∘C Those values correspond to the tan 120575peaks shown in Figure 5
Figure 6 also shows peaks between 110 and 130∘Cdue to119879119892
of starch which coincide with the 119879119892obtained by mechano-
dynamic tests which confirms that increasing fiber contentincreases 119879
119892
The endothermic peaks at the high temperature zonecorrespond to PLAmelting temperature (119879
119898) The peak tem-
perature values presented in Table 5 show that slight changesin PLA melting temperature correspond to an increase withPLA content and a decreasewithABF addition Such decreasecan be explained by the interference that fibers may cause toallow PLA crystallization Before the PLA melting peaks thecorrespondent small shoulder is attributed to rearrangementof lamellar fractions formed during PLA crystallization [34]or premelting of small crystals
34 Mechanostatical Tests Even though mechanodynamictests allowed the thermomechanical characterization of
Poly(lactic acid) (wt)0 10 20
Youn
g m
odul
us (M
Pa)
0
100
200
300
400
500
600
ABF content (wt)0
10
15
Figure 7 Young modulus of polymer blends and composites at25∘C varying PLA content
Poly(lactic acid) (wt)0 10 20
Flex
ural
mod
ulus
(MPa
)
0
500
1000
1500
2000
2500
3000
3500
ABF content (wt)0
10
15
Figure 8 Flexural modulus of polymer blends and composites at25∘C varying PLA content
extruded materials mechanostatic tests of some of the com-posites are included to confirm their moduli values patternas well as to determine impact resistance behavior In Figure 7Young modulus of polymer blends and composites as afunction of PLA and fiber content is shown The inclusionof PLA andor ABF promotes an increase in modulus Thosepatterns are in agreement with the storage modulus valuesobtained at 25∘C (Figure 4)
Figure 8 shows flexural modulus of the polymeric materi-als as a function of PLA and fiber content For this parameteran increase in PLA andor fiber content leads to composites
6 International Journal of Polymer Science
Poly(lactic acid) content (wt)0 10 20
0
2
4
6
8
10
12
14
16
18Im
pact
resis
tanc
e (kJ
m2)
Fiber content (wt)0
10
15
Figure 9 Impact resistance of polymer blends and composites at25∘C varying PLA content
with higher flexuralmodulus supporting the results obtainedfor the other moduli
In Figure 9 it can be noticed that the increase in rigidityof the TPS caused by the addition of PLA andor ABF leadsto a large decrease in impact resistance
35 Morphology In Figure 10 micrographs of fractured sam-ples of (a) TPS (b) polymer blend containing 20wt of PLAand (c) 80 TPS20 PLA ww with 15 wt ABF composite areshown In Figure 10(a) uniform gelatinized starch granulescan be observed Figure 10(b) shows a stratified brittle surfaceThe fibers in the composite can be seen in Figure 10(c) and arigid fracture is noticed
4 Conclusions
Blends of TPS and PLA and composites of TPSPLAABFprepared by extrusion followed by compressionmoldingwerecharacterized The reinforcing effect of PLA andor ABF inTPS led to an increase in moduli and a decrease in moistureabsorption and impact resistance The TPS glass transitiontemperature increased with ABF content and decreased withPLA content
The reinforcing effect of PLA was enhanced by theincorporation of ABF although the reduction in impactresistance is not convenientThat kind of behavior is expectedgenerically for rigidmaterials nevertheless thewood appear-ance and biodegradability along with the increase in modulias well as thermal resistance and the decrease in waterabsorption justify the production of this type of compositesfor many applications
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
(a)
(b)
(c)
Figure 10 SEM images of polymericmaterials (a) TPS (b) polymerblend containing 20wt PLA and (c) 80 TPS20 PLA ww with15 wt ABF composite
Acknowledgment
F J Aranda-Garcıa acknowledges CONACYT for a scholar-ship
International Journal of Polymer Science 7
References
[1] Institute for Bioplastics and Biocomposites and Nova-InstituteMore Bioplastic Statistic European Bioplastics 2014 httpwwwbio-basedeumarkets
[2] J L Guimaraes F Wypych C K Saul L P Ramos and K GSatyanarayana ldquoStudies of the processing and characterizationof corn starch and its composites with banana and sugarcanefibers from Brazilrdquo Carbohydrate Polymers vol 80 no 1 pp130ndash138 2010
[3] H Wang X Sun and P Seib ldquoEffects of starch moisture onproperties of wheat starchpoly (lactic acid) blend containingmethylenediphenyl diisocyanaterdquo Journal of Polymers and theEnvironment vol 10 no 4 pp 133ndash138 2002
[4] P Sarazin G Li W J Orts and B D Favis ldquoBinary andternary blends of polylactide polycaprolactone and thermo-plastic starchrdquo Polymer vol 49 no 2 pp 599ndash609 2008
[5] A Dufresne and M R Vignon ldquoImprovement of starch filmperformances using cellulosemicrofibrilsrdquoMacromolecules vol31 no 8 pp 2693ndash2696 1998
[6] H Liu F Xie L Yu L Chen and L Li ldquoThermal processing ofstarch-based polymersrdquo Progress in Polymer Science vol 34 no12 pp 1348ndash1368 2009
[7] J Girones J P Lopez P Mutje A J F Carvalho A A SCurvelo and F Vilaseca ldquoNatural fiber-reinforced thermoplas-tic starch composites obtained by melt processingrdquo CompositesScience and Technology vol 72 no 7 pp 858ndash863 2012
[8] R L Shogren ldquoPoly(ethylene oxide)-coated granular starch-poly(hydroxybutyrate-co-hydroxyvalerate) composite materi-alsrdquo Journal of Environmental Polymer Degradation vol 3 no2 pp 75ndash80 1995
[9] L Yu K Dean and L Li ldquoPolymer blends and composites fromrenewable resourcesrdquo Progress in Polymer Science vol 31 no 6pp 576ndash602 2006
[10] A Dufresne D Dupeyre and M R Vignon ldquoCellulosemicrofibrils from potato tuber cells processing and character-ization of starchndashcellulose microfibril compositesrdquo Journal ofApplied Polymer Science vol 76 no 14 pp 2080ndash2092 2000
[11] M J John and S Thomas ldquoBiofibres and biocompositesrdquoCarbohydrate Polymers vol 71 no 3 pp 343ndash364 2008
[12] M A Huneault andH Li ldquoMorphology and properties of com-patibilized polylactidethermoplastic starch blendsrdquo Polymervol 48 no 1 pp 270ndash280 2007
[13] L Jiang B Liu and J Zhang ldquoNovel high-strength thermo-plastic starch reinforced by in situ poly(lactic acid) fibrillationrdquoMacromolecular Materials and Engineering vol 294 no 5 pp301ndash305 2009
[14] E D M Teixeira A A S Curvelo A C Correa J MMarconcini G M Glenn and L H C Mattoso ldquoProperties ofthermoplastic starch from cassava bagasse and cassava starchand their blends with poly (lactic acid)rdquo Industrial Crops andProducts vol 37 no 1 pp 61ndash68 2012
[15] J Castano S Rodrıguez-Llamazares C Carrasco andR BouzaldquoPhysical chemical and mechanical properties of pehuen cellu-losic husk and its pehuen-starch based compositesrdquo Carbohy-drate Polymers vol 90 no 4 pp 1550ndash1556 2012
[16] W Smitthipong R Tantatherdtam and R Chollakup ldquoEffect ofpineapple leaf fiber-reinforced thermoplastic starchpoly(lacticacid) green composite mechanical viscosity and water resis-tance propertiesrdquo Journal ofThermoplastic CompositeMaterialsvol 28 no 5 pp 717ndash729 2015
[17] V A Alvarez and A Vazquez ldquoThermal degradation of cel-lulose derivativesstarch blends and sisal fibre biocompositesrdquoPolymerDegradation and Stability vol 84 no 1 pp 13ndash21 2004
[18] M Prajer and M P Ansell ldquoThermomechanical evaluation ofsisal-PLA compositesrdquo in Proceedings of the 17th InternationalConference on Composite Materials (ICCM rsquo09) pp 27ndash31 July2009
[19] E E M Ahmad and A S Luyt ldquoMorphology thermaland dynamic mechanical properties of poly(lactic acid)sisalwhisker nanocompositesrdquoPolymerComposites vol 33 no 6 pp1025ndash1032 2012
[20] A Campos K B R Teodoro E M Teixeira et al ldquoPropertiesof thermoplastic starch and TPSpolycaprolactone blend rein-forced with sisal whiskers using extrusion processingrdquo PolymerEngineering amp Science vol 53 no 4 pp 800ndash808 2013
[21] M E Vallejos A A S Curvelo EM Teixeira et al ldquoCompositematerials of thermoplastic starch and fibers from the ethanol-water fractionation of bagasserdquo Industrial Crops and Productsvol 33 no 3 pp 739ndash746 2011
[22] L Averous and N Boquillon ldquoBiocomposites based on plas-ticized starch thermal and mechanical behavioursrdquo Carbohy-drate Polymers vol 56 no 2 pp 111ndash122 2004
[23] R Belhassen S Boufi F Vilaseca et al ldquoBiocomposites basedon Alfa fibers and starch-based biopolymerrdquo Polymers forAdvanced Technologies vol 20 no 12 pp 1068ndash1075 2009
[24] L Averous C Fringant and L Moro ldquoPlasticized starch-cellulose interactions in polysaccharide compositesrdquo Polymervol 42 no 15 pp 6565ndash6572 2001
[25] A A S Curvelo A J F De Carvalho and J A M AgnellildquoThermoplastic starch-cellulosic fibers composites preliminaryresultsrdquoCarbohydrate Polymers vol 45 no 2 pp 183ndash188 2001
[26] M Wollerdorfer and H Bader ldquoInfluence of natural fibreson the mechanical properties of biodegradable polymersrdquoIndustrial Crops and Products vol 8 no 2 pp 105ndash112 1998
[27] A J F de Carvalho A A S Curvelo and J A M AgnellildquoWood pulp reinforced thermoplastic starch compositesrdquo Inter-national Journal of Polymeric Materials vol 51 no 7 pp 647ndash660 2002
[28] M N Angles and A Dufresne ldquoPlasticized starchtunieinwhiskers nanocomposites 1 Structural analysisrdquoMacromolecu-les vol 33 no 22 pp 8344ndash8353 2000
[29] M N Angles and A Dufresne ldquoPlasticized starchtunicinwhiskers nanocomposite materials 2 Mechanical behaviorrdquoMacromolecules vol 34 no 9 pp 2921ndash2931 2001
[30] A P Mathew and A Dufresne ldquoMorphological investigationof nanocomposites from sorbitol plasticized starch and tunicinwhiskersrdquo Biomacromolecules vol 3 no 3 pp 609ndash617 2002
[31] H Li andM A Huneault ldquoComparison of sorbitol and glycerolas plasticizers for thermoplastic starch in TPSPLA blendsrdquoJournal of Applied Polymer Science vol 119 no 4 pp 2439ndash24482011
[32] O Martin and L Averous ldquoPoly(lactic acid) plasticization andproperties of biodegradable multiphase systemsrdquo Polymer vol42 no 14 pp 6209ndash6219 2001
[33] W Jaafar W N Raihan S Siti Norasmah et al ldquoThermalproperties of PLAKenaf green nanocomposite effect of chemi-mechanical treatmentrdquo Advanced Materials Research vol 576pp 342ndash344 2012
[34] C Way D Y Wu D Cram K Dean and E Palombo ldquoPro-cessing stability and biodegradation of polylactic Acid (PLA)composites reinforced with cotton linters or maple hardwoodfibresrdquo Journal of Polymers and the Environment vol 21 no 1pp 54ndash70 2013
Submit your manuscripts athttpwwwhindawicom
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CorrosionInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Polymer ScienceInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CeramicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CompositesJournal of
NanoparticlesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Biomaterials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
NanoscienceJournal of
TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of
NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
CrystallographyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CoatingsJournal of
Advances in
Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Smart Materials Research
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MetallurgyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BioMed Research International
MaterialsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nano
materials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofNanomaterials
6 International Journal of Polymer Science
Poly(lactic acid) content (wt)0 10 20
0
2
4
6
8
10
12
14
16
18Im
pact
resis
tanc
e (kJ
m2)
Fiber content (wt)0
10
15
Figure 9 Impact resistance of polymer blends and composites at25∘C varying PLA content
with higher flexuralmodulus supporting the results obtainedfor the other moduli
In Figure 9 it can be noticed that the increase in rigidityof the TPS caused by the addition of PLA andor ABF leadsto a large decrease in impact resistance
35 Morphology In Figure 10 micrographs of fractured sam-ples of (a) TPS (b) polymer blend containing 20wt of PLAand (c) 80 TPS20 PLA ww with 15 wt ABF composite areshown In Figure 10(a) uniform gelatinized starch granulescan be observed Figure 10(b) shows a stratified brittle surfaceThe fibers in the composite can be seen in Figure 10(c) and arigid fracture is noticed
4 Conclusions
Blends of TPS and PLA and composites of TPSPLAABFprepared by extrusion followed by compressionmoldingwerecharacterized The reinforcing effect of PLA andor ABF inTPS led to an increase in moduli and a decrease in moistureabsorption and impact resistance The TPS glass transitiontemperature increased with ABF content and decreased withPLA content
The reinforcing effect of PLA was enhanced by theincorporation of ABF although the reduction in impactresistance is not convenientThat kind of behavior is expectedgenerically for rigidmaterials nevertheless thewood appear-ance and biodegradability along with the increase in modulias well as thermal resistance and the decrease in waterabsorption justify the production of this type of compositesfor many applications
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
(a)
(b)
(c)
Figure 10 SEM images of polymericmaterials (a) TPS (b) polymerblend containing 20wt PLA and (c) 80 TPS20 PLA ww with15 wt ABF composite
Acknowledgment
F J Aranda-Garcıa acknowledges CONACYT for a scholar-ship
International Journal of Polymer Science 7
References
[1] Institute for Bioplastics and Biocomposites and Nova-InstituteMore Bioplastic Statistic European Bioplastics 2014 httpwwwbio-basedeumarkets
[2] J L Guimaraes F Wypych C K Saul L P Ramos and K GSatyanarayana ldquoStudies of the processing and characterizationof corn starch and its composites with banana and sugarcanefibers from Brazilrdquo Carbohydrate Polymers vol 80 no 1 pp130ndash138 2010
[3] H Wang X Sun and P Seib ldquoEffects of starch moisture onproperties of wheat starchpoly (lactic acid) blend containingmethylenediphenyl diisocyanaterdquo Journal of Polymers and theEnvironment vol 10 no 4 pp 133ndash138 2002
[4] P Sarazin G Li W J Orts and B D Favis ldquoBinary andternary blends of polylactide polycaprolactone and thermo-plastic starchrdquo Polymer vol 49 no 2 pp 599ndash609 2008
[5] A Dufresne and M R Vignon ldquoImprovement of starch filmperformances using cellulosemicrofibrilsrdquoMacromolecules vol31 no 8 pp 2693ndash2696 1998
[6] H Liu F Xie L Yu L Chen and L Li ldquoThermal processing ofstarch-based polymersrdquo Progress in Polymer Science vol 34 no12 pp 1348ndash1368 2009
[7] J Girones J P Lopez P Mutje A J F Carvalho A A SCurvelo and F Vilaseca ldquoNatural fiber-reinforced thermoplas-tic starch composites obtained by melt processingrdquo CompositesScience and Technology vol 72 no 7 pp 858ndash863 2012
[8] R L Shogren ldquoPoly(ethylene oxide)-coated granular starch-poly(hydroxybutyrate-co-hydroxyvalerate) composite materi-alsrdquo Journal of Environmental Polymer Degradation vol 3 no2 pp 75ndash80 1995
[9] L Yu K Dean and L Li ldquoPolymer blends and composites fromrenewable resourcesrdquo Progress in Polymer Science vol 31 no 6pp 576ndash602 2006
[10] A Dufresne D Dupeyre and M R Vignon ldquoCellulosemicrofibrils from potato tuber cells processing and character-ization of starchndashcellulose microfibril compositesrdquo Journal ofApplied Polymer Science vol 76 no 14 pp 2080ndash2092 2000
[11] M J John and S Thomas ldquoBiofibres and biocompositesrdquoCarbohydrate Polymers vol 71 no 3 pp 343ndash364 2008
[12] M A Huneault andH Li ldquoMorphology and properties of com-patibilized polylactidethermoplastic starch blendsrdquo Polymervol 48 no 1 pp 270ndash280 2007
[13] L Jiang B Liu and J Zhang ldquoNovel high-strength thermo-plastic starch reinforced by in situ poly(lactic acid) fibrillationrdquoMacromolecular Materials and Engineering vol 294 no 5 pp301ndash305 2009
[14] E D M Teixeira A A S Curvelo A C Correa J MMarconcini G M Glenn and L H C Mattoso ldquoProperties ofthermoplastic starch from cassava bagasse and cassava starchand their blends with poly (lactic acid)rdquo Industrial Crops andProducts vol 37 no 1 pp 61ndash68 2012
[15] J Castano S Rodrıguez-Llamazares C Carrasco andR BouzaldquoPhysical chemical and mechanical properties of pehuen cellu-losic husk and its pehuen-starch based compositesrdquo Carbohy-drate Polymers vol 90 no 4 pp 1550ndash1556 2012
[16] W Smitthipong R Tantatherdtam and R Chollakup ldquoEffect ofpineapple leaf fiber-reinforced thermoplastic starchpoly(lacticacid) green composite mechanical viscosity and water resis-tance propertiesrdquo Journal ofThermoplastic CompositeMaterialsvol 28 no 5 pp 717ndash729 2015
[17] V A Alvarez and A Vazquez ldquoThermal degradation of cel-lulose derivativesstarch blends and sisal fibre biocompositesrdquoPolymerDegradation and Stability vol 84 no 1 pp 13ndash21 2004
[18] M Prajer and M P Ansell ldquoThermomechanical evaluation ofsisal-PLA compositesrdquo in Proceedings of the 17th InternationalConference on Composite Materials (ICCM rsquo09) pp 27ndash31 July2009
[19] E E M Ahmad and A S Luyt ldquoMorphology thermaland dynamic mechanical properties of poly(lactic acid)sisalwhisker nanocompositesrdquoPolymerComposites vol 33 no 6 pp1025ndash1032 2012
[20] A Campos K B R Teodoro E M Teixeira et al ldquoPropertiesof thermoplastic starch and TPSpolycaprolactone blend rein-forced with sisal whiskers using extrusion processingrdquo PolymerEngineering amp Science vol 53 no 4 pp 800ndash808 2013
[21] M E Vallejos A A S Curvelo EM Teixeira et al ldquoCompositematerials of thermoplastic starch and fibers from the ethanol-water fractionation of bagasserdquo Industrial Crops and Productsvol 33 no 3 pp 739ndash746 2011
[22] L Averous and N Boquillon ldquoBiocomposites based on plas-ticized starch thermal and mechanical behavioursrdquo Carbohy-drate Polymers vol 56 no 2 pp 111ndash122 2004
[23] R Belhassen S Boufi F Vilaseca et al ldquoBiocomposites basedon Alfa fibers and starch-based biopolymerrdquo Polymers forAdvanced Technologies vol 20 no 12 pp 1068ndash1075 2009
[24] L Averous C Fringant and L Moro ldquoPlasticized starch-cellulose interactions in polysaccharide compositesrdquo Polymervol 42 no 15 pp 6565ndash6572 2001
[25] A A S Curvelo A J F De Carvalho and J A M AgnellildquoThermoplastic starch-cellulosic fibers composites preliminaryresultsrdquoCarbohydrate Polymers vol 45 no 2 pp 183ndash188 2001
[26] M Wollerdorfer and H Bader ldquoInfluence of natural fibreson the mechanical properties of biodegradable polymersrdquoIndustrial Crops and Products vol 8 no 2 pp 105ndash112 1998
[27] A J F de Carvalho A A S Curvelo and J A M AgnellildquoWood pulp reinforced thermoplastic starch compositesrdquo Inter-national Journal of Polymeric Materials vol 51 no 7 pp 647ndash660 2002
[28] M N Angles and A Dufresne ldquoPlasticized starchtunieinwhiskers nanocomposites 1 Structural analysisrdquoMacromolecu-les vol 33 no 22 pp 8344ndash8353 2000
[29] M N Angles and A Dufresne ldquoPlasticized starchtunicinwhiskers nanocomposite materials 2 Mechanical behaviorrdquoMacromolecules vol 34 no 9 pp 2921ndash2931 2001
[30] A P Mathew and A Dufresne ldquoMorphological investigationof nanocomposites from sorbitol plasticized starch and tunicinwhiskersrdquo Biomacromolecules vol 3 no 3 pp 609ndash617 2002
[31] H Li andM A Huneault ldquoComparison of sorbitol and glycerolas plasticizers for thermoplastic starch in TPSPLA blendsrdquoJournal of Applied Polymer Science vol 119 no 4 pp 2439ndash24482011
[32] O Martin and L Averous ldquoPoly(lactic acid) plasticization andproperties of biodegradable multiphase systemsrdquo Polymer vol42 no 14 pp 6209ndash6219 2001
[33] W Jaafar W N Raihan S Siti Norasmah et al ldquoThermalproperties of PLAKenaf green nanocomposite effect of chemi-mechanical treatmentrdquo Advanced Materials Research vol 576pp 342ndash344 2012
[34] C Way D Y Wu D Cram K Dean and E Palombo ldquoPro-cessing stability and biodegradation of polylactic Acid (PLA)composites reinforced with cotton linters or maple hardwoodfibresrdquo Journal of Polymers and the Environment vol 21 no 1pp 54ndash70 2013
Submit your manuscripts athttpwwwhindawicom
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CorrosionInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Polymer ScienceInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CeramicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CompositesJournal of
NanoparticlesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Biomaterials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
NanoscienceJournal of
TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of
NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
CrystallographyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CoatingsJournal of
Advances in
Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Smart Materials Research
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MetallurgyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BioMed Research International
MaterialsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nano
materials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofNanomaterials
International Journal of Polymer Science 7
References
[1] Institute for Bioplastics and Biocomposites and Nova-InstituteMore Bioplastic Statistic European Bioplastics 2014 httpwwwbio-basedeumarkets
[2] J L Guimaraes F Wypych C K Saul L P Ramos and K GSatyanarayana ldquoStudies of the processing and characterizationof corn starch and its composites with banana and sugarcanefibers from Brazilrdquo Carbohydrate Polymers vol 80 no 1 pp130ndash138 2010
[3] H Wang X Sun and P Seib ldquoEffects of starch moisture onproperties of wheat starchpoly (lactic acid) blend containingmethylenediphenyl diisocyanaterdquo Journal of Polymers and theEnvironment vol 10 no 4 pp 133ndash138 2002
[4] P Sarazin G Li W J Orts and B D Favis ldquoBinary andternary blends of polylactide polycaprolactone and thermo-plastic starchrdquo Polymer vol 49 no 2 pp 599ndash609 2008
[5] A Dufresne and M R Vignon ldquoImprovement of starch filmperformances using cellulosemicrofibrilsrdquoMacromolecules vol31 no 8 pp 2693ndash2696 1998
[6] H Liu F Xie L Yu L Chen and L Li ldquoThermal processing ofstarch-based polymersrdquo Progress in Polymer Science vol 34 no12 pp 1348ndash1368 2009
[7] J Girones J P Lopez P Mutje A J F Carvalho A A SCurvelo and F Vilaseca ldquoNatural fiber-reinforced thermoplas-tic starch composites obtained by melt processingrdquo CompositesScience and Technology vol 72 no 7 pp 858ndash863 2012
[8] R L Shogren ldquoPoly(ethylene oxide)-coated granular starch-poly(hydroxybutyrate-co-hydroxyvalerate) composite materi-alsrdquo Journal of Environmental Polymer Degradation vol 3 no2 pp 75ndash80 1995
[9] L Yu K Dean and L Li ldquoPolymer blends and composites fromrenewable resourcesrdquo Progress in Polymer Science vol 31 no 6pp 576ndash602 2006
[10] A Dufresne D Dupeyre and M R Vignon ldquoCellulosemicrofibrils from potato tuber cells processing and character-ization of starchndashcellulose microfibril compositesrdquo Journal ofApplied Polymer Science vol 76 no 14 pp 2080ndash2092 2000
[11] M J John and S Thomas ldquoBiofibres and biocompositesrdquoCarbohydrate Polymers vol 71 no 3 pp 343ndash364 2008
[12] M A Huneault andH Li ldquoMorphology and properties of com-patibilized polylactidethermoplastic starch blendsrdquo Polymervol 48 no 1 pp 270ndash280 2007
[13] L Jiang B Liu and J Zhang ldquoNovel high-strength thermo-plastic starch reinforced by in situ poly(lactic acid) fibrillationrdquoMacromolecular Materials and Engineering vol 294 no 5 pp301ndash305 2009
[14] E D M Teixeira A A S Curvelo A C Correa J MMarconcini G M Glenn and L H C Mattoso ldquoProperties ofthermoplastic starch from cassava bagasse and cassava starchand their blends with poly (lactic acid)rdquo Industrial Crops andProducts vol 37 no 1 pp 61ndash68 2012
[15] J Castano S Rodrıguez-Llamazares C Carrasco andR BouzaldquoPhysical chemical and mechanical properties of pehuen cellu-losic husk and its pehuen-starch based compositesrdquo Carbohy-drate Polymers vol 90 no 4 pp 1550ndash1556 2012
[16] W Smitthipong R Tantatherdtam and R Chollakup ldquoEffect ofpineapple leaf fiber-reinforced thermoplastic starchpoly(lacticacid) green composite mechanical viscosity and water resis-tance propertiesrdquo Journal ofThermoplastic CompositeMaterialsvol 28 no 5 pp 717ndash729 2015
[17] V A Alvarez and A Vazquez ldquoThermal degradation of cel-lulose derivativesstarch blends and sisal fibre biocompositesrdquoPolymerDegradation and Stability vol 84 no 1 pp 13ndash21 2004
[18] M Prajer and M P Ansell ldquoThermomechanical evaluation ofsisal-PLA compositesrdquo in Proceedings of the 17th InternationalConference on Composite Materials (ICCM rsquo09) pp 27ndash31 July2009
[19] E E M Ahmad and A S Luyt ldquoMorphology thermaland dynamic mechanical properties of poly(lactic acid)sisalwhisker nanocompositesrdquoPolymerComposites vol 33 no 6 pp1025ndash1032 2012
[20] A Campos K B R Teodoro E M Teixeira et al ldquoPropertiesof thermoplastic starch and TPSpolycaprolactone blend rein-forced with sisal whiskers using extrusion processingrdquo PolymerEngineering amp Science vol 53 no 4 pp 800ndash808 2013
[21] M E Vallejos A A S Curvelo EM Teixeira et al ldquoCompositematerials of thermoplastic starch and fibers from the ethanol-water fractionation of bagasserdquo Industrial Crops and Productsvol 33 no 3 pp 739ndash746 2011
[22] L Averous and N Boquillon ldquoBiocomposites based on plas-ticized starch thermal and mechanical behavioursrdquo Carbohy-drate Polymers vol 56 no 2 pp 111ndash122 2004
[23] R Belhassen S Boufi F Vilaseca et al ldquoBiocomposites basedon Alfa fibers and starch-based biopolymerrdquo Polymers forAdvanced Technologies vol 20 no 12 pp 1068ndash1075 2009
[24] L Averous C Fringant and L Moro ldquoPlasticized starch-cellulose interactions in polysaccharide compositesrdquo Polymervol 42 no 15 pp 6565ndash6572 2001
[25] A A S Curvelo A J F De Carvalho and J A M AgnellildquoThermoplastic starch-cellulosic fibers composites preliminaryresultsrdquoCarbohydrate Polymers vol 45 no 2 pp 183ndash188 2001
[26] M Wollerdorfer and H Bader ldquoInfluence of natural fibreson the mechanical properties of biodegradable polymersrdquoIndustrial Crops and Products vol 8 no 2 pp 105ndash112 1998
[27] A J F de Carvalho A A S Curvelo and J A M AgnellildquoWood pulp reinforced thermoplastic starch compositesrdquo Inter-national Journal of Polymeric Materials vol 51 no 7 pp 647ndash660 2002
[28] M N Angles and A Dufresne ldquoPlasticized starchtunieinwhiskers nanocomposites 1 Structural analysisrdquoMacromolecu-les vol 33 no 22 pp 8344ndash8353 2000
[29] M N Angles and A Dufresne ldquoPlasticized starchtunicinwhiskers nanocomposite materials 2 Mechanical behaviorrdquoMacromolecules vol 34 no 9 pp 2921ndash2931 2001
[30] A P Mathew and A Dufresne ldquoMorphological investigationof nanocomposites from sorbitol plasticized starch and tunicinwhiskersrdquo Biomacromolecules vol 3 no 3 pp 609ndash617 2002
[31] H Li andM A Huneault ldquoComparison of sorbitol and glycerolas plasticizers for thermoplastic starch in TPSPLA blendsrdquoJournal of Applied Polymer Science vol 119 no 4 pp 2439ndash24482011
[32] O Martin and L Averous ldquoPoly(lactic acid) plasticization andproperties of biodegradable multiphase systemsrdquo Polymer vol42 no 14 pp 6209ndash6219 2001
[33] W Jaafar W N Raihan S Siti Norasmah et al ldquoThermalproperties of PLAKenaf green nanocomposite effect of chemi-mechanical treatmentrdquo Advanced Materials Research vol 576pp 342ndash344 2012
[34] C Way D Y Wu D Cram K Dean and E Palombo ldquoPro-cessing stability and biodegradation of polylactic Acid (PLA)composites reinforced with cotton linters or maple hardwoodfibresrdquo Journal of Polymers and the Environment vol 21 no 1pp 54ndash70 2013
Submit your manuscripts athttpwwwhindawicom
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CorrosionInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Polymer ScienceInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CeramicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CompositesJournal of
NanoparticlesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Biomaterials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
NanoscienceJournal of
TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of
NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
CrystallographyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CoatingsJournal of
Advances in
Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Smart Materials Research
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MetallurgyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BioMed Research International
MaterialsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nano
materials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofNanomaterials
Submit your manuscripts athttpwwwhindawicom
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CorrosionInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Polymer ScienceInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CeramicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CompositesJournal of
NanoparticlesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Biomaterials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
NanoscienceJournal of
TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of
NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
CrystallographyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CoatingsJournal of
Advances in
Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Smart Materials Research
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MetallurgyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BioMed Research International
MaterialsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nano
materials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofNanomaterials
