Polymer Blends and Composites...This course introduces students to multicomponent polymeric systems,...
Transcript of Polymer Blends and Composites...This course introduces students to multicomponent polymeric systems,...
Polymer Blends and Composites from Renewable Resources
Assoc.Prof. Dr. Jatuphorn Wootthikanokkhan School of Energy, Environment and Materials,
King Mongkut’s University of Technology Thonburi (KMUTT), Thailand
School of Energy, Environment and Materials
KMUTT
About this course
MTT692 Special Topics: Polymer Blends and Composites from Renewable Resources
Course description
This course introduces students to multicomponent polymeric systems, particularly those based on blends and composite materials. Specifically, this course focuses on the use of natural and renewable materials such as cellulose micro/nano fibers, biodegradable aliphatic polyesters, thermoplastic starch and natural rubber. Fundamental concepts and mechanisms related to the development of blends and composites materials will be described. Case studies involving compounding formulations and applications of some selected polymer blends and composites systems will also be introduced and discussed.
MTT692 Special Topics: Polymer Blends and Composites from Renewable Resources
Objectives:
By the end of this course, the students should be able to;
1) Understand the fundamental concepts of blends and composites 2) Understand structure-properties relationships of polymer blend and composites
3) Identify techniques that can be used for preparing and fabricating polymer blends and composites
Lecturers:
Assoc.Prof.Dr.Jatuphorn Wootthikanokkhan (65%) (JWN)
Dr. Supachok Tanpichai (28 %) (STI) Assoc.Prof. Ekachai Wimolmala (7%) (EWA)
Measurements
Lecturers
Midterm exam.
Final exam.
Presentation &
Report
Total
Assoc.Prof.Dr.Jatuphorn Wootthikanokkhan
40
5
20
65
Dr. Supachok Tanpichai
-
30
-
30
Assoc.Prof. Ekachai Wimolmala
-
5 -
5
Textbooks & References 1. W.J. Work, K. Horie, M. Hess, R.F.Stepto, Definitions of terms related to polymer blends, composites, and multiphase polymeric materials, Pure Appl.Chem. 76(2004)1985-2007 2. L.Yu, K. Dean, L.Li, Polymer blends and composites from renewable resources, Prog. Polym. Sci, 31(2006)576-602. 3. Polymeric Multicomponent Materials, edited by L.H.Sperling, John Wiley & Sons, Inc., Canada, 1997 4. Polymer Blends and Alloys, edited by M.J.Folkes and P.S.Hope, Chapman & Hall, UK, 1993 5. Rubber Toughened Engineering Plastics, edited by A.A.Collyer, Chapman & Hall, Great Britain, 1994 6. Polymer Toughening, edited by C.B.Arends, Marcel Dekker, Inc., USA, 1996 7. Polymer Blends, edited by D.R.Paul et.al, Academic Press, USA, 1978 8. Polymer Blends, edited by D.R.Paul and C.B.Bucknall, John Wiley & Sons, USA, 2000 9. J.S.Miles & S.Rostami, Multicomponent Polymer Systems, Longman Scientific & Technical, Great Britain, 1992. 10. An introduction to composite materials by D Hull 11. Introduction to polymers by Robert J Young 12. Engineering mechanics of composite materials by Isaac M Daniel 13. Fiber-reinforced composites : materials, manufacturing, and design by P. K Mallick 14. Polymer nanocomposites : processing, characterization, and applications by Joseph H Koo 15. Polymer nanocomposites : synthesis, characterization, and modeling by Krishnamoorti and Richard A Vaia 16. Polymeric foams : science and technology byShau-Tarng Lee 17. The Science and Technology of Rubber by Jame E. Mark, Burak Erman & C. Michael Roland, 4th Ed., Elsevier, Oxford, UK, 2013 18.Handouts.
JWN
14/01/59
Introduction
Polymers from renewable resource, miscibility and compatibility in polymer blends, types of morphology of immiscible blends
JWN
21/01/59
Thermodynamic of polymer blend Gibbs free energy equation, Role of solubility parameter, determinations the solubility parameter (by calculating via a group molar attraction constant and/or by experiments), factors affecting polymer miscibility & the phase diagram , assessments of polymer–polymer miscibility
JWN
28/01/59
Compatibilizers and compatibilization Types of compatibilizers (block- graft- copolymers), some common compatibilizers and their preparation methods, effects of compatibilizers on structure and properties of polymer immiscible blends, characterization of interdiffusion and interfacial profiles, reactive compatibilization
JWN
04/02/59 Blending techniques, melt blending, solution blending, IPNs, reactive blending, freeze dry blending
JWN
11/02/59
Rubber toughened plastics Structure of rubber toughened plastics and toughening mechanisms, role of particle size, ligament thickness, rubber volume fraction and cross-linking of the rubber phase, percolation model, interfacial model, particle concentration model,
JWN
18/02/59
PLA and the related blends, toughening of PLA, impact modifiers for PLA, structure-properties relationships of rubber toughened PLA, PLA/starch blends, thermoplastic starch, compatibilizer for PLA/starch blends, reactive blending, structure-properties relationships of PLA/starch blends
JWN
25/02/59
Summary & review
03/03/59 Midterm Examination
JWN
10/03/59
Natural rubber blends Effect of mal-distribution of crosslink on properties of elastomer blends, determination of
crosslink distribution in elastomer blends, Factors affecting distribution of curatives, effects of distribution of carbon black on properties of elastomer blends, determination of distribution of carbon black in elastomer blends, factors affecting carbon black distribution
EWA
17/03/59
Applications of natural rubber and elastomer blends
Selected materials based on elastomer blend for oil resistant properties and progress in developments of materials for natural rubber roofs composite applications.
STI
24/03/59
Introduction to green composites
Definition, advantages and disadvantages and limitation of the green composites
STI
31/03/59
Cellulose micro/nano fiber as a reinforcing agent
Compositions, types and properties of cellulose nanofibers and preparation method STI
07/04/59
Processing & applications of green composites
Processing techniques and applications STI
21/04/59
Structure-properties relationships of green composites
Rule of mixtures, reinforcement distribution, interaction of the matrix and reinforcement
JWN, STI, EWA
28/04/59
Student presentations
on structure-properties-applications relationship of some recently developed polymer blends and green composite for commercial uses.
12/05/59 Final Examination
Dr.J.Wootthikanokkhan, KMUTT
Definitions
“A polymer blend is a member of a class of materials analogous to metal alloys, in
which at least two polymers are blended together to create a new material with different
physical properties.” [Gert R. Strobl (1996). The Physics of Polymers Concepts for Understanding Their
Structures and Behavior]
“Composite is a multicomponent material comprising multiple different (nongaseous)
phase domains in which at least one type of phase domain is a continuous phase”
“Polymer composite refers to the composite in which at least one component is a
polymer” (W.J.Work et al., Pure Appl. Chem. 76(2004)1985-2007)
Dr.J.Wootthikanokkhan, KMUTT
Varieties of polymers architecture and their combinations
Dr.J.Wootthikanokkhan, KMUTT
Some reasons for blending
Enhancement of physical properties of some polymers
Improving process-ability of some polymers Economy purpose Recycling
Dr.J.Wootthikanokkhan, KMUTT
Santoprene (Thermoplastic vulcanizate [TPV] based on PP/EPDM)
(Ref: Asian plastic news, october, 2005)
Dr.J.Wootthikanokkhan, KMUTT
Makroblend (PC/PET blend) from Bayer
Better thermal stability, chemical resistance, paint-ability
REF: Asian plastic news, september, 2005
Dr.J.Wootthikanokkhan, KMUTT
Advantages of polymer blending
Relative ease of blending techniques as compared to synthesis of new polymers.
Large scale production is cheaper than polymer synthesis
More environmental friendly process than the synthesis (lower
usage of solvents and monomers)
Classification of polymer blends
(Adapted from “Polymer Alloy Compendium; A Technical note from JICA short course in High Performance
Polymer Technology”)
Terms related to polymer blend miscibility (Ref. form Utracki, in Polymer Blend Handbook, 2002, p. 135, ch. 2, Kluwer Academic Publisher.)
Term Definition
Miscible polymer blend Polymer blend, homogeneous down to the molecular level, in which the domain size is comparable to macromolecular dimension.
Immiscible blend Polymer blends whose change in free energy of mixing is greater than zero.
Polymer Alloy Immiscible, compatibilized polymer blend with the modified interface and morphology
Interphase Third phase in binary polymer alloys, endangered by inter-diffusion or compatibilization. Its thickness ~ 2 to 60 nm, depends on polymer mescibility and compatibilization
Compatibilization Process of modification of the inter-phase in immiscible polymer blends, resulting in reduction of the interfacial energy, development and stabilization of the desired morphology, leading to the creation of a polymer alloys with enhanced performance
Dr.J.Wootthikanokkhan, KMUTT
Examples of some miscible and immiscible blends
Miscible blends
– PS/PPO, – PVC/NBR, – PVC/polyesters, PET/PBT, – PVDF/PMMA
Immiscible blends
– High impact polystyrene (HIPS) (PS+ polybutadiene),
– PE/PP
Dr.J.Wootthikanokkhan, KMUTT
Some types of morphology in immiscible blends
Dispersed particle morphology
A desired structure for toughening plastics
Sub-inclusion or composite droplet
Co-continuous morphology
Like a water soaked sponge, both phase are continuous
Fibrillar morphology
Dr.J.Wootthikanokkhan, KMUTT
PS/polybutadiene immiscible blend
Dr.J.Wootthikanokkhan, KMUTT
TEM micrograph of PVC/MBS blend stained with OsO4 (Ref: Encyclopedia of PVC, LI. Nass et.al., Marcel Dekker, NY, 1988)
Dr.J.Wootthikanokkhan, KMUTT
Morphology changes with composition
Morphology of NR/ACM (50/50 % w/w) blend
Dr.J.Wootthikanokkhan, KMUTT
Fibrillar morphology
SEM micrograph showing morphology of NR/ACM (20/80 % w/w) blend
Dr.J.Wootthikanokkhan, KMUTT
Dispersed particle morphology with sub-inclusion of PS phase in rubber particles
Miscibility and compatibility of blends
Miscible & Immiscible blends (Classified on the basis of phase separation and phase size)
Compatible- and Incompatible blends (Classified on the basis of interfacial adhesion and mechanical strengths)
Tg and Tm values (from DSC) of PVDF/PMMA blends [Ref: Polymer Science and Technology, J.R. Fried,, 1995]
SEM micrograph showing poor interfacial adhesion in PS/PE blend [Ref: E. Grulke, Polymer Process Engineering, 1993]
Dr.J.Wootthikanokkhan, KMUTT
Compatibilization of incompatible blends using block- and graft copolymers
SEM micrograph showing a better interfacial adhesion in PS/PE blend after adding hydrogenated STYRENE-BUTADIENE block copolymer [Ref: E. Grulke, Polymer Process Engineering, 1993]
Dr.J.Wootthikanokkhan, KMUTT
Effects of block copolymer on morphology and mechanical properties of NR/ACM
Materials from renewable resources
Dr.J.Wootthikanokkhan, KMUTT
Monomers, polymers and composites from renewable resources
This course focuses on the following high potential materials; Poly(lactic acid) as a biodegradable plastic
Starch as a thermoplastic material
Cellulose and bacteria cellulose for uses as both reinforcing agents for
composites AND standalone films/sheets Natural rubber as bio-based elastomeric materials
Dr.J.Wootthikanokkhan, KMUTT
Definitions
• Renewable resources may be defined as resources (solar, soil trees) that have the potential to be replaced over time by natural processes.
• Biomass is the material of biological origin, excluding materials embedded in geological formation and/or fossilized
• Bio-based means derived from biomass • Bio-based product refer to the product which is wholly or partly bio-
based
• Biodegradable plastics are plastics that decompose by the action of living organisms, usually bacteria
Biopolymers versus biodegradable polymers
Biopolymers include PLA, natural rubber Not all biopolymers are biodegradable On the other hand, some synthetic polymers can also be
biodegradable such as PCL, PBS
Classification of biodegradable polymers
(Adapted from L. Averous, J.Macromol.Sci., Polym.Rev.C4(3)2004, 231-274)
Comparisons of some biodegradable polymers
Polymer Performance factors
Advantages Disadvantages Potential applications
Starch Ratio of amylose to amylopectin
Low cost, rapid degradation
Hydrophilicity There are a number of applications where biodegradable polymers would be desirable, including disposable food items, bags, foam, agricultural film, and some injection molded products. Most of these items are currently produced from PE and PS.
Cellulose acetate Degree of substitution
Tensile strength DS > 2.2 reduces biodegradation
PHA Side-chain length, copolymer ratio
Rapid biodegradation, water stable
Cost
PVOH Molecyular weight, percent hydrolysis
Good oxygen barrier, rapid biodegradation
Solubility in water
PCL Molecular weight, crystallinity
Water stable, biodegradable, toughness
Low melting point
PLA D:L ratio, molecular weight
Tensile strength, clear film
Brittle
PLA as a biodegradable polymer
Cost and production level of some biodegradable polymers
Polymer Cost ($ per lb)*
Principal mode of production
Production level (lb per years) *
Starch 0.15 - 0.80 Plant biomass > 230 billion
Cellulose acetate 1.70 Chemical modification of polysaccharides (cotton,
wood pulp)
2.3-2.4 billion
Poly(hydroxybutyrate-co-valerate
6.00 - 8.00 Bacterial fermentation 660,000
PVOH 1.50 - 2.50 Polymerization of vinyl alcohol
150-200 million
Polycaprolactone (PCL)
2.70 Polymerization of caprolactone
< 10 million
Poly(lactic acid), [PLA]
1.00 – 3.00 Polymerization of lactic acid
10 million
* Ref: Trends in Polymer Science, 2 (1994) 230
Physical and mechanical properties of some biodegradable polymers
Polymer Tg
(°C)
Tm
(°C)
Td
(°C)*
Tensile Strength
(MPa)
Elongation
(%)
PHA (- 50) – (+5) 54 -175 - ≤ 40 No data
PHB 5 175 - 40 -
PHBV (12 % V) - 138 297 25 20
PHBV (24 % V) - - - 15 -
PHOct (-35) 55 290 9 380
PVA (or PVOH) 58 – 85 180 – 240 - 40 – 50 300 – 400
PCL -60 55 – 65 250 21 – 31 600 – 1000
PLA 50 - 59 130 - 196 245 50 3
* Ref: Trends in Polymer Science, 2 (1994) 230
Materials used for the production of lactic acid
35
From lactic acid to lactides
36
• Lactide is obtained by depolymerization of low Mw PLA to give a mixture of D
and L lactide (or meso Lactide)
• The differences percentage of lactide isomer formed depends on lactic acid
isomer feedstock, temp. and catalyst.
• A mixture of D and L lactide (1/1) can form racemic stereocomplex which melt at 230 °C
and have superior mechamical properties than either pure polymers
PLA Polymerization
37
Degradation of PLA
Commercial PLA
• Commercial PLA such as NatureWorks® are copolymer of PLLA and PDLLA,
• Various grades are available with different in terms of D-lactide content
• 4032-D (1-2 % D-lactide) • 4042-D (3-5 % D-lactide) • 4060-D (11-13 % D-lactide)
• PLA resins of high D-content (4-6%) would be more suitable for thermoformed, extruded, and blow molded.
Comparison between PLLA and PDLLA
Polymer Crystallinity Tg (°C) Degradation Rate
PLA (L form)
Semi Crystalline (Tm = 173-178 °C)
60-65 > 2 Years
PLA (D,L form)
Amorphous 55-60 12-16 months
Last retrieved on February, 2012 http://www.drugdeliverytech.com/ME2/dirmod.asp?sid=&nm=&type=Publishing&mod=Publications%3A%3AArticle&mid=8F3A7027421841978F18BE895F87F791&tier=4&id=BB85E8579021481EACBC7C3F0674348F 40
ผลของ stereochemistry และ crystallinity
ตอสมบตเชงกลของ PLA
(From Garlotta, 2002) 41
ผลของ stereochemistry
ตอสมบตทางความรอนของ PLA
(From Lim et al., 2008) 42
Applications of PLA
43
Processing of PLA
Extrusion
Extrusion blown film process Injection moulding
Injection stretch blow moulding
Thermoforming 44
Problems of PLA
1. PLA is brittle 2. Melt strength of the PLA is inherently low 3. Cost of the PLA is relatively high 4. PLA is thermally unstable, it can be degraded during the processing
due to; • Hydrolysis • Chain scission
Some polymers used for blending with PLA
Patents Polymers Purpose
US patent 7,354,973 B2 Ethylene copolymers (EGMA, EPDM, EBA, Ionomer)
Toughening
US Patent 5,498,650 (1996) US patent 7,138,439 (2006)
Copolyesters
US Patent 7,368,503 (2008) PCL (with P(MMA-co-GMA) as a compatibilizer)
US Patent 7,393,590 B2 (2008) PCL using peroxides as a
compatibilizer
US Patent 5,922,832 Epoxidized Natural Rubber & MA-g-PB (reactive compatibilizer)
US Patent 7,214,414B2 Ecoflex, Biomax
Impact strength & processability,
US Patent 5,939,467 [1999] PCL Aliphatic polyester PU
Rheological properties (melt
strength, viscosity)
Some commercial impact modifiers for PLA
Trade Name Manufacturers Chemistry of the materials
Comments
Biostrength®130 Arkema Core-shell particle Impact modifier (Transparent)
Biostrength®150 Arkema Core-shell particle
Impact modifier (Opaque)
Biostrength 700 Arkema Acrylic copolymer •Melt strength enhancer •Transparency is maintained
Biomax®Strong 100
DuPont Ethylene copolymer Impact modifier for PLA. Non-food packaging
Biomax®Strong 120
DuPont Ethylene copolymer Impact modifier for PLA Food packaging
EMforce®Bio Specialty mineral Impact modifier
Paraloid [BPMS250] Rohm and Haas Acrylic polymer •No effect on film clarity •FDA and EU (Directive2002/72/EC) approved
Starch as a thermoplastic materials
48
Structures of starch granule
Phase transitions of starch
Adapted from M.B.K.Naizi, also available from http://www.rug.nl/research/portal/files/6572065/08_diss.pdf (January, 2016)
ภาพถาย SEM ของแปงปกตและแปงเทอรโมพลาสตก
51 Thermoplasic starch, TPS Normal starch (un-modified)
700x
400x
THERMOPLASTIC STARCH: DEFINITION AND PROPERTIES
Plasticizers for TPS
Water (Hulleman et.al., 1998) Glycerol (Rosa et.al., 2007, 2009) Sorbitol (Yang et.al., 2006, Bourtoom, 2008) Urea (Ma et.al., 2004, 2006) Citric acid (Wang et.al., 2007) Formamide (Ma et.al., 2004)
TPS containing only water has poor mechanical properties The plasticizers intereac with starch molecules via a hydrogen bonding
Physical and mechanical properties of some biodegradable polymers
Polymer Tg (°C)
Tm (°C)
Td (°C)*
Tensile Strength
(MPa)
Elongation (%)
Starch 230 220-240 220 NT NT
Starch (7% H2O) 140 - - NT NT
Starch (7% H2O)
18 - - NT NT
Cellulose acetate (DS = 2.5)
190 230-250 - 17-50 10-30
* Td = decomposition temp.
** NT = not testable
* Ref: Trends in Polymer Science, 2 (1994) 230
TPS blends
TPS is blended for mainly two purposes; 1. To improve such its properties as water resistance and
mechanical performance
2. To use it as a modifier for other polymers, with the purpose of increasing the biodegradability and/or decreasing the cost of the blends
Derivatives of polysaccharide
Cellulose acetate is obtained by reacting cellulose with acetic anhydride Degree of substitution is expressed as DS. The maximum value of DS = 3 for
polysacharide The cellulose acetate has tensile strength comparable to polystyrene, which make the
polymer suitable for injection moulding
The rate of biodegradation decrease with the DS value
Various acylating agents
Acylating agents Disadvantages
Acetic anhydride
Prohibited
Propionic anhydride Expensive
Maleic anhydride Staining, induced crosslinking
Acyl halides Less reactive than anhydrides
Natural rubber as a source of bio-based elastomeric products
Classification of rubbers
Rubbers
ยางธรรมชาต (ยางพารา)
Natural Rubber
ยางสงเคราะห
Synthetic Rubbers
นอกจากนน ยางสงเคราะห ยงสามารถแบงยอยไดดงน
1. ยางสาหรบงานทวไป (Commodity rubbers) เชน IR (Isoprene Rubber) BR (Butadiene
Rubber)
2. ยางสาหรบงานสภาวะพเศษ (Specialty rubbers) เชน การใชงานในสภาวะอากาศรอนจด
หนาวจด หรอ สภาวะทมการสมผสกบนามน ไดแก Silicone, Acrylate rubber เปนตน
Natural rubber Polyisoprene, high green strength, low cost. But poor oil & heat resistance
Synthetic rubbers
SBR, BR, IR Oil and heat resistance rubber e.g. NBR, AR(ACM), FKM
Assoc. Prof. Dr. Jatuphorn Wootthikanokkhan, KMUTT
Natural rubber (cis 1,4-polyisoprene)
Chemical structure of NR based on Gutta Percha (trans-1,4-
polyisoprene) (a) and Heavea Rubber (cis-1,4- polyisoprene) (b)
Chemical structure of NR based on Gutta Percha (trans-1,4-polyisoprene) (a)
and Heavea Rubber (cis-1,4- polyisoprene) (b)
(a)
(b)
Assoc. Prof. Dr. Jatuphorn Wootthikanokkhan, KMUTT
Stereoisomers of 1,4-polyisoprene (a) cis, (b) trans
Figure from S.L. Rosen, Fundamental principles of polymeric materials, John Wiley & Sons, 1993, p. 36
Compositions of NR latex
Composition Content (%)
Rubber 30.0-40.0
Protein 2.0-2.5
Organic compound 2.0-3.0
Ash 0.7-0.9
Water 55.0-60.0
] R.K. Han, in Rubber Engineering, Chapter 9, McGraw-Hill, New York, 2001, pp. 425-432.
Assoc. Prof. Dr. Jatuphorn Wootthikanokkhan, KMUTT
จะตองนานายางมาผานกระบวนการซงม ขนตอนดงน
– เตมโซเดยมเมตะไบซลไฟทลงในน ายางเพอเพมความขาว
– เตมกรดฟอรมคหรอกรดอะซตคเพอใหเนอยางตกตะกอนและจบตว
เปนกอนทงไวเปนเวลา 10-12 ชวโมง
– นาเนอยางทไดไปทาการรดใหเปนแผน จากนนทาการรมควนตอไป
การเกด cross-linking ในยาง
• ในทน คาวา Curing, Crosslinking, และ
Vulcanization มความหมายเดยวกน
• สวนใหญ อาศยปฏกรยาเคม และความรอน
กระตน
• อาจจะทาในโมลด (mould) ในระหวางขนตอน
การขนรป หรออาจจจะทาในเตาอบ (hot air
oven) หลงขนรปแลวกได
Assoc. Prof. Dr. Jatuphorn Wootthikanokkhan, KMUTT
Cross-linking systems for elastomers
Elastomers Cross-linking systems
Polychloroprene
MgO, ZnO with or without accelerator
Fluoroelastomer a) Diamine, or b) Bisphenol compounds, or c) Peroxide and triazine
Acrylate copolymers a) poly-or diamines, or b) Sodium stearate and sulfur
Carboxylate rubber
a) Metal oxide with or without sulfur b) Peroxides, or c) Epoxides and polyols
Polysiloxane a) Peroxide (high temperature), or b) Metal catalysts moisture (RTV)
Assoc. Prof. Dr. Jatuphorn Wootthikanokkhan, KMUTT
ผลกระทบของปรมาณพนธะขาม • ผลของการเกดโครงสรางแบบ crosslink
– ทนการละลาย
– ทนความรอน
– มความยดหยน อลาสตก
สมบตของยางธรรมชาต
• มคาอณหภมการเปลยนสถานะคลายแกว (glass transition temperature, tg) ประมาณ
-70 องศาเซลเซยส
• มความทนทานตอนากรดเจอจาง ดาง และเกลอไดด
• มความสามารถในการยดตวไดสงและสามารถคนตวไดด ทงนเนองจากยางธรรมชาตม
นาหนกโมเลกลสงมาก และมสายโซโมเลกลทคอนขางยาวแลวมการพนกน (entanglement) ทาให
เกดการเชอมโยงในลกษณะโครงสรางตาขายแบบหลวม ๆ เมอไดรบแรงกระทาจากภายนอก จะทา
ใหสายโซโมเลกลทจากเดมพนกนอยมการยดตวตามทศทางของแรง และมการจดเรยงตวกนอยางม
ระเบยบสามารถเกดผลกได ดงนนยางธรรมชาตจงมสมบตเดนในดานของความแขงแรง
Assoc. Prof. Dr. Jatuphorn Wootthikanokkhan, KMUTT
การนายางธรรมชาตไปใชงาน 1. เนองจากยางธรรมชาตมสมบตดเยยมในดานการทนตอแรง
ดงและมความยดหยนสงมากแมไมไดเตมสาร เสรมแรง จง
เหมาะทจะใชในการผลต ถงมอยาง ถงยางอนามย และ
ลกโปง เปนตน
2. ยางธรรมชาตมสมบตทงเชงกลและพลวตทด มความรอน
สะสมทเกดขณะใชงานตา และมสมบต ความเหนยวตดกนท
ด จงเหมาะทจะนาไปใชในการผลตเปน ยางลอรถบรรทก
หรอใชผสมกบยางสงเคราะหในการผลตลอรถยนต ฝายยาง
ยางกนกระเเทกทาเรอ เปนตน
Assoc. Prof. Dr. Jatuphorn Wootthikanokkhan, KMUTT
ขอจากดของยางธรรมชาต • ยางธรรมชาตทมพนธะคทวองไวตอการเกดปฏกรยาอยดวย จง
สงผลกระทบในเรองของความสามารถในการตานทานตอ
ออกซเจน แสงแดด และโอโซนทตา โดยยางธรรมชาตจะ
เกดปฏกรยาออกซเดชนตรงบรเวณพนธะคได
• นอกจากนนการทโมเลกลของยางธรรมชาตประกอบ
ไปดวยอะตอมคารบอนและไฮโดรเจนเปนหลก จงทา
ใหโมเลกลของยางธรรมชาตจงมสภาพความเปนขว
ตา และมความสามารถในการทนตอนามนและตวทา
ละลายอนทรยทไมมขวไดต า
Assoc. Prof. Dr. Jatuphorn Wootthikanokkhan, KMUTT
เปรยบเทยบสมบตดานการทนความรอนและนามนของยางธรรมชาตกบยางสงเคราะหชนดตางๆ
Elastomer blends and research issues
Uneven distribution of curatives in rubber-rubber blends
Mal-distribution of reinforcing fillers in the elastomer blends
Topics for next week
Thermodynamic of polymer blends Assessment of polymers miscibility