EFFECT OF COMPATIBILIZER ON THE BRITTLE-DUCTILE TRANSITION BEHAVIOR OF PP/POE BLENDS

The PP/POE blends with different contents of compatibilizer were prepared by melt mixing process, and the brittle-ductile transition behavior, thermal property and mechanical performance of the PP/POE blends were examined. The results showed that the addition of ethylene-propylene block copolymer based compatibilizer decreased the brittle-ductile transition temperature of PP/POE blends accordingly. AFM results suggested that proper contents of compatibilizer induced the well dispersion and phase morphologies of POE particles in PP matrix. STEM results showed that the compatibilizer decreased the critical interparticle distance (IDc) of POE domains,leading to their homogeneous distribution. The dispersed POE particles and PP matrix diffused and interpenetrated into each other near the edge of their interfaces, indicating the improvement of the blend systems' compatibility. When the content of compatibilizer reached 10%, the small and well homogenous POE domains were obtained and the obvious hard core - tough shell structures of POE domains were formed. The average diameter of POE domains was 0.54 mu m and the interparticle distance was 0.1 mu m. The DSC curves during the cooling and the second heating runs demonstrated that the incorporation of proper content of compatibilizer could enhance the crystallization degree of PP/POE blends. Mechanical testing data illustrated that the addition of compatibilizer not only enhanced the toughness of PP/POE blends and decreased their brittle-ductile transition temperature, but also maintained the materials' stiffness, so the stiffness-toughess balance of the PP/POE blends was well kept.