Nanocomposite thermoplastic elastomers

Among all LRP methods, ATRP is the most studied and since 1995, when it was rst reported, a very large number of articles have appeared on this topic. An excellent review written by the pioneer in the eld, Matyjaszewski (Matyjaszewski and Xia, 2001) covers the development in ATRP from 1995 till the end of 2000. ATRP can provide extraordinary control over topologies, compositions, microstructures, and functionahties. This has led to the production of a vast array of polymeric materials with application in nanocomposites, thermoplastic elastomers, bioconjugates, drug dehvery systems, etc. 

Presents current research activities on new rubbers, thermoplastic elastomers, nanocomposites, biomaterials, and smart polymers, as well as rubber blends, composites, and rubber ingredients... 

FIGURE 4.2 Continuous structures of polymer nanocomposites. (A) SEM image of thermoplastic elastomer/CNT composite with CNT dispersed in polymer matrix. (B) SEM image of PPy/Au nanocomposite with ordered porous structure. (C) SEM image of P(VDF-HFP)/Si02 composite with porous structure. (D) TEM image of PEDOT/graphene composite with a multilayer structure. (A) Reproduced with permission from reference Koemer, H., Price, G., Pearce,... 

Koerner, H., Price, G., Pearce, N.A., Alexander, M., Vaia, R.A. (2004) Remotely actuated polymer nanocomposites - stress-recovery of carbon-nanotube-filled thermoplastic elastomers. Nature Materials, 3, 115-120. 

She has pnbhshed more than 45 papers in intematiorral and national refereed journals, more than 60 publications in conference proceedings, and more than 20 invited lectures for international conferences. She has been one of the editors of Malaysian Journal of Chemistry, Berita IKM- Chemistry in Malaysia, and books pnbhshed by Royal Society of Chemistry entitled Natural Rubber Materials, Volume 1 Blends and IPNs and Volume 2 Composites and Nanocomposites. She peer-reviews a few international journals on polymer science. Her research interest is devoted to modified natural rabber-based thermoplastic elastomers, biodegradable polyester/polyether blends, and solid polymer electrolytes... 

The resulting films display the t ical properties of a thermoplastic elastomer. Depending on the conditions of purification, also fully amorphous poly(/3-hydroxyoctanoate) films can be obtained. Nanocomposite materials can be prepared when using this latex as a matrix and using in addition a colloidal suspension of hydrolyzed starch or cellulose whiskers as a natural and biodegradable filler. The properties are strongly dependent on the aspect ratio of the whiskers (23). 

Pramanik, M., Srivastava, S. K., Samantaray, B. K., and Bowmick, A. K. 2002. Synthesis and characterization of organosoluble, thermoplastic elastomer/clay nanocomposites. Poh nerSaence Pmri Polymer Physics 40 2065-2072. 

Nanocomposite technology using small amounts of silicate layers can lead to improved properties of thermoplastic elastomers with or without conventional fillers such as carbon black, talc, etc. Mallick et al. [305] investigated the effect of EPR-g-M A, nanoclay and a combination of the two on phase morphology and the properties of (70/30w/w) nylon 6/EPR blends prepared by the melt-processing technique. They found that the number average domain diameter (Dn) of the dispersed EPR phase in the blend decreased in the presence of EPR-g-MA and clay. This observation indicated that nanoclay could be used as an effective compatibilizer in nylon 6/EPR blend. X-ray diffraction study and TEM analysis of the blend/clay nanocomposites revealed the delaminated clay morphology and preferential location of the exfoliated clay platelets in nylon 6 phase. 

Sanchez studied the functionalization of oxidized SWCNTs and MWCNTs dispersed in thermoplastic elastomers based on poly(butylene terephthalate) (PBT)/ poly(tetramethylene oxide) (PTMO). These nanocomposites showed good dispersion and enhancement in thermo-oxidative stability [27]. 1 % of pristine multi-walled carbon nanotube (MWCNTs) were dispersed in silicon rubber. The SR nanocomposites showed 28 % better thermal stability and 100 % improvement in the ultimate tensile strength is achieved as compared with the pristine polymer matrix counterpart [28]. Also ionic liquids have been tested to improve the dispersion and thermal stability of MWCNTs in polychloroprene rubber (CR) showing improvement in these properties [29]. On the other hand the effect of carbon nanofiber on nitrile rubber was studied. It has been found that the nanofiber increase the thermal stability and decrease the flammability [4]. 

Prado, LASdA, Kopyniecka, A., Chandrasekaran, S., Broza, G., Roslaniec, Z., Schulte, K. Impact of filler functionalization on the crystallinity, thermal stability and mechanical properties of thermoplastic elastomer/crbon nanombe nanocomposites. Macromol. Mater. Eng. 298, 359-370 (2013)... 

Naderil, G., Razavi-Nouril, M.,Taghizadeh, E., Lafleur, P.G. and Dubois, C. (2011), Preparation of thermoplastic elastomer nanocomposites based on polyamide-6/ polyepichlorohydrin-co-ethylene oxide , Polymer Engineering Science, Vol. 51, No. 2, pp. 278-284. 

Koemer H et al (2004) Remotely actuated polymer nanocomposites—stress-recovery of carbon-nanotube-lilled thermoplastic elastomers. Nat Mater 3(2) 115-120... 

The use of a commercial Cloisite 20A organoclay to prepare SBS-based nanocomposites by melt processing was recently reported [63]. In this case, the nanocomposite morphology was characterized by a combination of intercalated and partly exfoliated clay platelets, with occasional clay aggregates present at higher clay content. For this particular thermoplastic elastomer nanocomposite system, well-dispersed nanoclays lead to enhanced stiffness and ductility, suggesting promising improvements in nanocomposite creep performance. The use of stearic acid as a surface modifier of montmorillonite clay to effectively improve the clay dispersion in the SBS matrix and the mechanical properties of the SBS-clay nanocomposites was reported [64]. 

Halbach TS, Thomann Y, Mulhaupt R (2008) Boehmite nanorod-reinforced-polyethylenes and ethylene/l-octene thermoplastic elastomer nanocomposites prepared by in situ olefin polymerization and melt compounding. J Polym Sci A Polym Chem 46 2755-2765... 

Hemmati M, Narimani A, Shariatpanahi H (2011) Study on morphology, rheology and mechanical properties of thermoplastic elastomer polyolefin (TPO)/carbon nanotube nanocomposites with reference to the effect of polypropylene-grafted-maleic anhydride (PP-g-MA) as a compatibilizer. Int J Polym Mater 60 384—397... 

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