Polyamide organoclay nanocomposite

A typical shish-kebab crystalline structure has been foimd by Maiti and Okamoto (2003) and Kim et al. (2001) in polyamide/organoclay nanocomposite and by Choi and Kim (2004) in PP/EPR/talc nanocomposite where a preferential orientation of polymer lamellae perpendicular to the surface of organoclay layers was inspected by TEM measurements. The unique observation of lamellar orientation (Ml the clay layers was ascribed to nucleation and epitaxial crystallization at the interface between layered silicate and polymer matrix especially the surfaces of clay platelets acted as heterogeneous nucleation sites. Orientation of iPP crystals was also enhanced in rPP/PP-MA/o-MMT injection-moulded parts, especially manufactured by dynamic packing injection moulding (Wang et al. 2005). MMT... 

L. Song, Y. Hu, Z. Lin, S. Xuan, S. Wang, Z. Chen, and W. Fan, Preparation and properties of halogen-free flame-retarded polyamide 6/organoclay nanocomposite, Polym. Degrad. Stabil., 2004, 86 535-540. 

Chow, W. S., Mohd Ishak, Z. A., Karger-Kocsis, J., Apostolov, A. A., and Ishiaku, U. S. 2003. Compatibilizing effect of maleated pol5 ropylene on the mechanical properties and morphology of injection molded polyamide 6/pol5 ropylene/organoclay nanocomposites. 44 7427-7440. 

Isik, L, Yilmazer, U., and Bayram, G. 2008. Impact modified polyamide-6/organoclay nanocomposites Processing and characterization. Polymer Composites 29 133-141. 

I. Goitisolo, J.I. Eguiazabal, J. Nazabal, Structure and properties of an hybrid system based on bisphenol A polycarbonate modified by A polyamide 6/organoclay nanocomposite, European Polymer Journal 44 (7) (2008) 1978-1987. 

The main uses of montmorillonite stem from its characteristic expansion, and it is used to control viscosity or impart thixotropy to a variety of liquid polymers based on unsaturated polyesters, PVC plastisols, polysulfides, alkyds, etc. It has also been reported to control the melt rheology of thermoplastics and to reinforce polyamides. There has, over the last few years, been enormous industrial and research interest, with many papers and patents, published on montmorillonite, especially as an organoclay as the basis of polymer nanocomposites. Because of the delamination process described above plastic-organoclay nanocomposites have been reported to have very high rigidity, low permeability to fluids, and fire resistance. This subject is covered in more detail in Chapter 10. 

For other polyamide/clay nanocomposites, PA 11/OMMT nanocomposites were prepared by Zhang, Yu, and Fu [30] via in situ intercalative polymerization. The polymerization involved two steps first the cation exchange of MMT with 11-aminolauric acid, and then the polymerization of 11-aminolauric acid in the presence of OMMT. The crystallization rate of the PA 11 matrix was obviously improved by the nanoscale-dispersed MMT clay. A similar in situ polymerization of exfoliated PAll/MMT nanocomposites containing different amounts of MMT was performed by Yang and co-workers [31]. First, 11-aminoundecanoic acid was mixed with organoclay in a vessel, and then the mixtures were heated to 100-150 °C to drive off the water and heated again to 230-260 °C for 4 h to achieve polymerization. 

Table 11.3. Mechanical properties of neat polyamide 66 (BO), polyamide 66/organoclay nanocomposite (95/5) (Bl), polyamide 66/SEBS-g-MA binary blend (85/15) (B2), and ternary nanocomposites, N1 to N4 [143]...

V. M. Karaman, V. F. Shumsky, E. G. Privalko, V. P. Privalko, B. Lehmann, K Friedrich (2003) Viscoelastic behaviour of polyamide 6/organoclay nanocomposites in the melt state, Phys. Condens. Polym. Syst. (Rivne), in press. 

Chow WS et al. Compatibilizing effect of maleated polypropylene on the mechanical properties and morphology of injection molded polyamide 6/polypropylene/organoclay nanocomposites. Polymer 2003 44(24) 7427-7440. 

FIGURE 7 The data ofthe X-ray analysis for organoclay and nanocomposite polyamide acid/ organoclay. 

The quantity of the hterature in the field of the nanocomposite polymeric materials has grown multiple times in recent years. The possibility to use almost all polymeric and polycondensated materials as a matrix is shown The nanocomposites from various organoclays and polymers have been synthesized. Here is just a small part of the compounds for being the matrix referenced in literature polyacrylate [83], polyamides [82,84,85], polybenzoxazine [86], polybutylene terephtalate [11,82,87], polyimides [88], polycarbonate [89], polymethylmetaciylate [90], polypropylene [91,92], poly-... 

---