Nanocomposites polyamide 66/organoclay

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

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... 

The data for nanocomposites polymer/organoclay on the basis of polyamide-6 (PA-6), polyamide-12 (PA-12), polystyrene (PS) and polypropylene (PP), which are listed in table 11.1, were used for the relationships structure-flame-resistance characteristics. The maximum rate of heat release measured with the use of a cone calorimeter according to the standards ASTM 1354-92 and ISO/DIS 13927 [2], the values of which are also listed in Table 11.1, was used as flame-resistance characteristic of the indicated nanomaterials. 

Chiu et al [134] also prepared polyamide 6 ternary nanocomposites with organoclay (5 wt%) and maleated polyolefin elastomer (10 wt%) as fillers. Izod impact strength of this ternary nanocomposite was 51.6 J/m, which was much higher than the binary clay nanocomposite (22.8 J/m) and neat polyamide (37.7 J/m), but significantly lower than the tough binary blend (104.8 J/m). This again ascertains the necessity to have a higher rubber content of >15 wt%... 

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. 

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-... 

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. 

Despite the small-scale appUcation of the IPC technique, several researchers have reported on the formation of PAs nanocomposites by the relevant process. Kalkan et al. [78] studied the formation of PA 6.6-clay nanocomposites, in the case of either organically modified or pristine (Na ) clay [79]. In the first case [78], they found that in order to achieve better clay dispersion, stirring during the mixing process of the two phases, that is, the clay-containing adipoyl chloride toluene dispersion and hexamethylenediamine aqueous solution, is essentiaL Nevertheless, in the case of a polar treated organoclay, where anticipated favorable interactions between the surfactant and the polar polyamide chains should yield a... 

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. 

L. Cui, J. E. Bara, Y. Brun, Y. Yoo, P. J. Yoon, and D. R. Paul, Polyamide- and polycarbonate-based nanocomposites prepared from thermally stable imidazolium organoclay. Polymer, 50 (2009), 2492-502. 

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. 

E. Erdmann, M. L. Dias, V. Pita, F. Monasterio, D. Acosta, and H. A. Destefanis, Effect of the Organoclay Preparation on the Extent of the Intercalation/Exfoliation and the Barrier Properties in Polyamide-6/Montmorillonite Nanocomposites, ed. D. S. Dos Santos (Rio de Janeiro Trans Tech Publications Ltd., 2006), pp. 78-84. 

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