Analysis of Polymer Nanocomposite

8/12/2019 Analysis of Polymer Nanocomposite

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ANALYSIS OF INSULATING NANOCOMPOSITEPOLYMERV.Kartheek,Student,GITAM University,C h.N.S.Kartheek ,Student, GITAM University

A.Tej Abhilash,Student, GITAM University,G.Satya Chandu, Student, GITAM University

Abstract:

The Study of physical properties of polymernanocomposites mechanical failure andthermal softening in polyamide (PA, nylon)6 nanocomposites. The nanocompositesexhibited failure due to thermal softeningwhen the maximum local temperature of thespecimens subjected to loading reached theglass transition temperature. Further, thestress (S) versus life (N) test data of polymernanocomposites are well described byBasquinslaw.

INTRODUCTIONPolymer/layered silicates nanocompositeshave received a great deal of attention sincetheir first demonstration by the Toyotagroup in 1987 [1]. These nanocompositesexhibit superior properties such as highertensile strength, modulus, heat resistance,light weight, and less permeability to gas ata lower level of loading relative toconventionally scaled composites.Nowadaysthe preparation system of layered silicatenanocomposites is very abundant, manysurfactants are used to modifymontmorillonite [2,3], such asaminododecanoic acid, octadecylammoniumetc., while no work has been reported toguide the selection of surfactants fordifferent polymers and different processingmethods systematically.Nylon 66 is a

versatile engineering plastics, the successfuldevelopment of nylon 6 nanocompositesinspired us to study nylon 66montmoriilonite nano c omposites. There isfew reports involving nylon 66nanocomposites some of which show that

relative to nylon 6, nylon66/montmorillonite hybrids show lessenhancement [4]. According to the classicaltheories of filler reinforcement [5], theextent of property enhancement depends onmany factors including the aspect ratio ofthe filler, its degree of dispersion and theadhesion at the filler/matrix interface.It isconcluded that for polar polymer, such asnylon 66, the combination with pristine clay

produces the highest binding energy of all

and nanocomposites produced fromuntreated clays should be the toughest.Though the assumption that the clay

platelets are exfoliated into individual platelets does not reflect the actual state ofthe clay platelets in the nanocomposites, theresult is still illuminating.Becausemontmorillonite has neither good interactionwith organic polymers to achieve gooddispersion nor adequate adhesion, it iscertainly not applicable for preparation of

nanocomposites by melt compounding withuntreated clay [1]. Based on this concept, inorder to maximize the total potential energyand to match the polarity of nylon 66,montmorillonite was co-treated withoctadecylammonium and aminoundecanoicacid in this paper. Then nylon 66nanocomposites were prepared with


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different co-treated montmorillonites viamelt compounding and effect ofmontmorillonite on properties ofnanocomposites was investigated andanalyzed.

Nano composites:

Mixture of Montmorillonite andPolyamides

Fig1: Nano composite

Montmorillonite:

Montmorillonite is a very soft phyllosilicategroup of minerals that typically form inmicroscopic crystals, forming a clay.Montmorillonite, a member of the smectitefamily, is a 2:1 clay, meaning that it has 2tetrahedral sheets sandwiching a centraloctahedral sheet. The particles are plate-shaped with an average diameter ofapproximately one micrometre. Members of

this group include saponite.Montmorilloniteis the main constituent of the volcanic ashweathering product, bentonite.The watercontent of montmorillonite is variable and itincreases greatly in volume when it absorbswater. Potassium, iron, and other cations arecommon substitutes, the exact ratio ofcations varies with source. It often occurs

intermixed with chlorite, muscovite, illite,cookeite, and kaolinite.

Preparation of organophilic montmorillonite

[1] 120 g of montmorillonite were dispersedin 1200 ml of distilled water by vigorousstirring at 80 _C and the montmorillonitedispersion was derived; slightly excessiveamounts of octadecylammonium andaminoundecanoic acid with different molarratio (1/1, 1/2), acidified by appropriateamount of concentrated hydrochloric acid,were dispersed into 600 ml alcohol and 600ml distilled water separately, and thesolutions were called octadecylammonium

alcoholic solution and aminoundecanoicacid aqueous solution, respectively; Thenthe latter two were added to themontmorillonite dispersion and the resultantsuspension was vigorously stirred foranother 8 h at 80 _C. The co-treatedmontmorillonites were repeatedly washed byalcohol and distilled water at 50 _C until noAgCl precipitate occurred at roomtemperature when the filtrates were titratedwith 0.1 N AgNO3. The filtered cakes werethen dried in vacuo at 80 _C for 12 h. Thedried cakes were ground and screened with a325-mesh sieve to obtain the co-treatedmontmorillonites and were termed M11 andM12, respectively. The organophilicmontmorillonites mono-treated byoctadecylammonium or aminoundecanoicacid were prepared as widely described andwere termed M10 and M01 here. All thedried organophilic montmorillonites werekept in a sealed desiccators and ready fornext experiments.

Polyamides:Materials

Nylon 66 used in the present work is acommercially available material with Mw of14,000. The sodium montmorillonite (Na-MMT) is refined and ground to an average


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particle size of 12 lm with a cation exchangecapacity (CEC) of 115 meq/100 g.Octadecylammonium, 11-aminoundecanoicacid and other reagents are analyticallypureand are used without further purification.

Preparation of organophilicmontmorillonite [1]

120 g of montmorillonite were dispersed in1200 ml of distilled water by vigorousstirring at 80 _C and the montmorillonitedispersion was derived; slightly excessiveamounts of octadecylammonium andaminoundecanoic acid with different molar

ratio (1/1, 1/2), acidified by appropriateamount of concentrated hydrochloric acid,were dispersed into 600 ml alcohol and 600ml distilled water separately, and thesolutions were called octadecylammoniumalcoholic solution and aminoundecanoicacid aqueous solution, respectively; Thenthe latter two were added to themontmorillonite dispersion and the resultantsuspension was vigorously stirred foranother 8h at 80 _C. The co-treatedmontmorillonites were repeatedly washed byalcohol and distilled water at 50 _C until noAgCl precipitate occurred at roomtemperature when the filtrates were titratedwith 0.1 N AgNO3. The filtered cakes werethen dried in vacuo at 80 _C for 12 h. Thedried cakes were ground and screened with a325-mesh sieve to obtain the co-treatedmontmorillonites and were termed M11 andM12, respectively. The organophilicmontmorillonites mono-treated byoctadecylammonium or aminoundecanoicacid were prepared as widely described andwere termed M10 and M01 here. All thedried organophilic montmorillonites werekept in a sealed desiccators and ready fornext experiments.

Preparation of nanocomposites

Prior to each processing step, all nylon 66containing materials were dried in vacuo forat least 24 h at 80 _C to avoid moistureinduced degradation reactions. Composites

were prepared by melt compounding using atwin extruder with zone I at 265 _C, zone IIat 265 _C, zone III at 265 _C, zone IV at265 _C, zone V at 265 _C, and headtemperature at 270 _C. For comparison, neatnylon 66 was also extruded in the twinextruder at the same processing conditions.The dried pellets were injected to standardtesting specimens for characterization andtests.


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Paraffin type bilayer

Intercalated dispersion of polymernanocomposites Conclusion:

Heat treatment and mechanical properties:when compared with normal PA 6,6 thecomposite perfoms will it has more meltingtemperature, tensile modulus and strengthsubstainality increases and heat distortiontemperature (HDT) increases by 23.2K

References

[1] Kaviratna PD, Pinnavaia TJ andSchroeder PA, J. Phys. Chem. Solids 1996;57:12: 1897.

[2] Sherman LM, Plastics Technology, June

1999; 52

[3] Brundle R. C., Evans C., Wilson S.,Encyclopedia of Materials Characterization,Butterworth-Heinemann, 1992; 60-69.

[4] Hackett E, Manias E and Giannelis EP,J. Chemical Phys. 1998; 108:17: 7410.

[5] Usuki A, Kojima Y, Kawasumi M,Okada A, Fukushima Y, Kurauchi T andKamigaito O, J. Mater. Res. 1993; 8:5: 1174

[6] Lan T, Kaviratna PD and Pinnavaia TJ,Chem. Mater. 1995; 7: 2144.

[7] Vaia Ra, Vasudevan S, Krawiec W,Scanlan LG and Giannelis EP, Adv. Mater.1995; 7:2: 154.

[8]Messermith PB and Giannelis EP, J.Polymer Sci. 1995; 33: 1047.


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Analysis of Polymer Nanocomposite

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