Study on the compatibilization of PC/ABS blend and the synthesis of triblock copolymer as a new compatibilizer for PC/ABS blend

Abstract

Due to the combined good processability of ABS with excellent mechanical proper-ties, impact and heat resistance of polycarbonate (PC), PC/acrylonitrile-butadiene-styrene (ABS) blend is one of the most important materials in fabrication of various parts for auto-mobiles, household electric appliances and mobile. Although it has an adequate adhesion between PC and styrene-acrylonitrile (SAN) copolymer, PC/ABS blend is incompatible thermodynamically. Therefore, practical problems relating with non-uniform state of dis-persion and unstable morphology that may have occurred during injection molding process, which may lead to quality deterioration of final products. Thus the compatibilization for the PC/ABS blend should be required. The goal of this study is to understand the effect of structural factors of components and the effect of the synthesized new compatibilizer on the morphology and rheological properties of immiscible PC/ABS blend. In chapter 2, as representative of PC/ABS blends, we have studied phase morpholo-gy and interfacial tension in blends of PC/SAN. To confirm how the acrylonitrile (AN) con-tent of the SAN polymer influences its phase morphology and rheology, PC/SAN (90/10) blends with varying AN content, ranging from 24 to 41 wt% with respect to the SAN, were prepared using a twin-screw extruder. The interfacial tension of the blends was determined from the measured average particle radius and the relaxation time of the interface using Palierne’s emulsion model. The minimum interfacial tension and domain size occurred in the blend containing AN 28.5 wt% versus SAN. The interfacial tension results were consistent with the observed morphology and rheology of the blends. Because the viscosity of SAN polymers varied with the AN content and molecular weight, the effect of the viscosity ratio was also examined by Wu’s empirical expression. In chapter 3, the effects of grafting structure of ABS on the morphology and rheo-logical properties of PC/ABS b...