PP-EPR二嵌段共聚物作PP/EPT共混增容剂的探讨

对以实验室合成的PP-EPR二嵌段共聚物作为PP/EPT二元共混物的增容剂进行了探讨。共混物在增容前后的物理力学性能的变化说明PP-EPR对PP/EPT共混物具有优良的增容效果;同时又有克服通常因橡胶增韧塑料而强度下降的优点。形态结构的表征结果说明共混物为两相结构,阐明了PP-EPR的作用以及低温冲击强度大幅度提高和在增容后抗张强度损失减少的原因。     

INVESTIGATION OF PP-EPR DIBLOCK COPOLYMER AS COMPATIBILIZER FOR PP/EPT BLEND

Blending isotactic polypropylene (PP) with ethylene-propylene terpolymer (EPT) is one of thesimplest and most effective ways for toughening PP. In order to further improve the toughness ofPP/EPT blend and to enhance the stability of the dispersed rubber phase, a diblock copolymer com-posed of PP and ethylene-propylene rubber blocks (PP-EPR) was added into the blend, as it is con-sidered that "forced compatibility" of the two components will be effected through the two chemi-cally bonded blocks, while two-phase structure still remains. Experimental results indicate that PP-EPR is an effective compatibilizer for PP/EPT blend. Itnot only increases the toughness of the blend, but also decreases the loss of tensile strengths usuallyaccompanying the toughening of plastics with an elastomer, which is very well explained by the mor-phological structure changes when an appropriate amount of PP-EPR was added into the blend.