Polyamide nanocomposite

Table 3.7 displays property examples for polyamide nanocomposites processed by various methods. 

Table 6.24 displays examples of polyamide nanocomposite properties according to the processing method. 

In polyamide nanocomposites (39), the storage modulus of the composites was reported to increase steadily with increasing the loading of MWNTs. At 2 wt% concentration of the nanotubes, the storage modulus of the nanocomposite was measured to be 1.97 GPa, which is an increase of 54% than the storage modulus of 1.28 GPa for the pure polyamide matrix. 

Boutti S, Bourgeat-Lami E, Zydowicz N (2005) Silica/polyamide nanocomposite synthesis via an original double emulsification process in miniemulsion. Macromol Rapid Commun 26 1860-1865... 

Jadav, G. L. and Singh, P. S. 2009. Synthesis of novel sdica-polyamide nanocomposite membrane with enhanced properties. Journal of Membrane Science 328 251-261. 

Nishitani, Y. Ohashi, K. Sekiguchi, I. Ishii, C. Kitano, T. (2010). Influence of Additon of Styrene-Ethylene/Butylene-Styrene Copolymer on Rheological, Mechanical and Tribological Properties of Polyamide Nanocomposites. Polymer Composites, Vol.31, No.l, pp. 68-76 ISSN 0272-8397... 

In this method, clay is first ion-exchanged using an organic compound in order for the monomer to be intercalated into the layers of the clay. The monomers that form the intercalated layer will become a polymerized interlayer. The authors succeeded in producing a polyamide nanocomposite for the first time using this method. The details will be described in Sect. 3. The basic concept of the technique is as follows. 

In clay-polyamide nanocomposites, effective exfoliation and dispersion of clay can be obtained by in-situ polymerization technique. In this process, layered silicate particles are dispersed in the monomer and then polymerized. It is done by ring-opening polymerization of e-caprolactum in the presence of organically modified clay [7-8,40-41]. 

Figure 9.8 Schematic view of clay-polyamide nanocomposite preparation in two stages. Reprinted from [53] with permission from Elsevier. 

Figure 9.14 Steady shear viscosity at 235°C for polyamide, in-situ polymerized polyamide nanocomposites and melt-blended polyamide nanocomposites. Reprinted from [61] with permission from Elsevier.

The clay platelets may not exfoHate fully in melt blending technique. Homogeneously exfoliated clay platelets can be obtained in in-situ polymerized polyamide nanocomposites [54]. These structrues can be observed only from transmission electron micrographs, since the XRD patterns may... 

The enhanced thermal stability at lower clay concentration will be helpful for producing clay-polyamide nanocomposites easily and economically. Exfoliated nanocomposites show better thermal stability than intercalated nanocomposites. The TGA data also reveal that the thermal stability of nanocomposites with 1 wt% clay concentration is not significantly... 

Na-MMT, the debonding is limited to polyamide nanocomposite and hence its property is comparatively better than Na and alkylammonium treated MMT. 

Figure 9.45 Wear volume loss and coefficient of friction vs load for Neat polyamide-66, Clay-polyamide-66, Clay-polyamide nanocomposites with SEBS-g-MA as compatibilizer. Reprinted from [1111 with permission from Elsevier.

The oxygen permeability in general decreases by 50 percent in polyamide matrix on nano-clay incorporation. Clay-polyamide nanocomposites can be used for packaging of processed meats, cheese, confectionery, cereals and boil-in-the-bag foods also for extrusion-coating applications in association with paperboard for fruit juice and dairy products, together with co-extrusion processes for the manufacture of beer and carbonated drink bottles (www.tifac.org). The nanocomposite packaging enhances the shelf life of many types of food. 

Kelnar, L, Kotek, J., Kapralkova, L., and Mrmteanu, B. S. 2005. Polyamide nanocomposites with improved toughness. Journal of Applied Polymer Science 96 288-293. 

Kouini B, Serier A. Properties of polypropylene/polyamide nanocomposites prepared by melt processing with a PP-g-MAH compatibilizer. Mater Des 2012 34 313-318. 

Nakamtua, K. (2004) Examining progress towards developing polyamide nanocomposites for automotive applications. Proceedings of the Nanocomposites 2004, Conference, European Plastics News, Bmssels, Belgiiun, March 17-18, 2004. 

S. Bourbigot, F. Samyn, T. Turf, S. Duquesne, Nanomorphology and reaction to fire of polyurethane and polyamide nanocomposites containing flame retardants. Polymer Degradation and Stability 95 (3) (2010) 320-326. 

In-situ intercalation method was reported by Toyota researchers for the synthesis of polyamide nanocomposites that led to the exponential growth in the nanocomposites research. For generation of polymer nanocomposites by this method, the layered silicate mineral is swollen in monomer. After swelling, the polymerization of the monomer is initiated. As monomer is present in and out of the filler interlayers, therefore, the generated stmcture is exfoUated or significantly intercalated. As the rate or mechanism of polymerization in and out of the filler interlayers... 

Concerning the commercialization of polyamides nanocomposites, the first product was launched in 1987 by Toyota, and was a 4wt% PA 6-day nanocomposite shaped as timing belt cover to be used in Starlet (Figure 2.6). The pertinent... 

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