Polyamides nanocomposites with

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.

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

Practically all the polymers can be processed to make nanocomposites. This emerging technology is developing in polyamide andTPO nanocomposites with applications in the automotive industry, and there are experiments with saturated polyesters, acrylics, polystyrenes... 

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. 

Mdszdros, L. and T. Czvikovszky. 2007. Polyamide-6 nanocomposites with electron-beam-treated clay. Radiation Physics and Chemistry 76 1329-1332. 

The introduction of nanoceramics in thermoplastics or thermosets seems to be a promising route to improving mechanical moduli, particularly of elastic matrices. The macroscopic properties are governed by the nature of polymer-nanoparticle interactions. In this chapter, specific attention will be paid to nanocomposites of polyamide (PA) with HAp. Considering their attractive viscoelastic properties, semiaromatic polyamides (e.g., PA-llTlO) have been chosen as the matrix [Choe et al., 1999]. Recently, several publications have been devoted to one-dimensional nanostructures with high-aspect-ratio particles. Promising data have been obtained for the polymer/nanowire-nanotube nanocomposites. 

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. 

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 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... 

The mechanical properties of in-situ polymerized and melt-blended hybrid nanocomposite with neat polyamide are discussed [61]. Table 9.12 summarizes the tensile properties of neat polyamide-6 and clay-polyam-ide nanocomposites. The tensile modulus of melt-blended nanocomposites is significantly higher than neat polyamide-6 and in-situ polymerized nanocomposites. 

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. 

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. 

The co-continuous structure and the final rheological properties of an immiscible polymer blend are generally controlled by not only the viscoelastic and interfacial properties of the constituent polymers but also by the processing parameters. For example, the effect of plasticizer on co-continuity development in blends based on polypropylene and ethylene-propylene-diene-terpolymer (PP/EPDM), at various compositions, was studied using solvent extraction. The results showed more rapid percolation of the elastomeric component in the presence of plasticizer. However, the same fuUy co-continuous composition range was maintained, as for the non-plasticized counterparts (Shahbikian et al. 2011). It was also shown that the presence of nanoclay narrows the co-continuity composition range for non-plasticized thermoplastic elastomeric materials (TPEs) based on polypropylene and ethylene-propylene-diene-terpolymer and influences their symmetry. This effect was more pronounced in intercalated nanocomposites than in partially exfoliated nanocomposites with improved clay dispersion. It seems that the smaller, well-dispersed particles interfere less with thermoplastic phase continuity (Mirzadeh et al. 2010). A blend of polyamide 6 (PA6) and a co-polyester of... 

In contrast, Wu et al. [75] formed PA 10.12-clay nanocomposite through the anhydrous melt polycondensation of the relevant salt. In the derived nanocomposite, clay platelets were exfoliated, developing strong interaction with the polyamide - a fact that was considered to endow the nanocomposite with higher tensile strength and higher tensile modulus. Moreover, the nanocomposite exhibited a reduction in water absorption as a result of barrier properties enhancement. 

Q. Q. Yang, Z. X. Guo, and J. Yu, Preparation and characterization of polyamide 66/montmorillonite nanocomposites with methyl methacrylate as cointercalation agent. Journal of Applied Polymer Science, 108 (2008), 1-6. 

FIGURE 2.8 Tensile moduli (relative to bulk value) for various nanocomposites (a) polyamide-6/MMT nanocomposites, with low-, medium-, and high- molecular weight polyamide-6 matrix, as an example of high improvement in mechanical properties due to effective stress transfer from polymer to filler (b) polyurethane and polyurethane copol3mers/MMT nanocomposites, as an example of high improvement in mechanical... 

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