Preparation, Morphology, Structure And Properties Of Several Kinds Of Biodegradable Polymer Blends And Polymer Nanocomposites

In recent years, conventional plastics have been widely used which caused severe environmental problems. Therefore, biodegradable polymers have received more and more attention because of the environmental benign property. However, the application of the biodegradable polymers has been badly limited because of the relatively higher price, narrower processing window and poorer mechanical properties. The modificaition of industrial biodegradable polymer is a meaningful project and of great importance.The polymer blending and nanocompounding with solution casting method were employed in this work. According to the special interaction between two neat components, a series of miscible crystalline/amorphous polymer blends and compatible organolclay nanocomposites were prepared. The influence of compositions, processing conditions to the morphology and crystallization was studied. It will be usefull in designing the polymer blend or composite materials with comprehensive properties.1. The miscibility and crystallization behavior of crystalline/amorphous polymer blends Four miscible crystalline/amorphous polymer blends have been prepared by solution-casting method. The single composition dependent glass transition temperature and the negative polymer-polymer interaction parameter indicate the complete miscibility of the polymer blends. The influence of the addition of amorphous polymer on the crystallization behavior and microstructure of crystalline polymer was also studied. The overall crystallization rates of crystalline polymer decrease with increasing crystallization temperature and the amorphous content in the blends; however, the crystallization mechanism of crystalline polymer does not change in the blends. The microstructural parameters, including the long period, thickness of crystalline phase and thickness of amorphous phase, change with increasing the amorphous content.2. Poly(butylene adipate-co-terephthalate) (PBAT)/organo-modified montmorillonite nanocompositesBiodegradable PBAT/C30B intercalated and exfoliated nanocomposites were fabricated by solution casting method to study the effect of clay loadings on the crystallization behavior, thermal stability, and dynamical mechanical properties of PBAT in the PBAT/C30B nanocomposites. X-ray diffraction and transmission electron microscopy results indicate the formation of exfoliated nanocomposites at low clay loadings less than 5 wt% and the mixture of exfoliated and intercalated nanocomposite at 8 wt% clay content throughout the PBAT matrix. Nonisothermal melt crystallization studies indicate that C30B enhances the crystallization of PBAT apparently due to the heterogeneous nucleation effect. Moreover, an attempt has been made to study the influence of the presence of C30B and its contents on the nucleation activity of PBAT quantitatively in the PBAT/C30B nanocomposites. It is also found that the thermal stability of PBAT decreases slightly in the nanocomposites. However, the storage modulus of PBAT increases apparently with increasing the C30B loadings in the PBAT/C30B nanocomposites.