Evaluation of compatibility in SAN/EPDM blends by determination of the adhesion parameters

摘要

A series of various types (different structures) of ethylene-polypropylene-diene-graft-poly-styrene (EPDM-g-PS) copolymers were synthesized and their surface property variations were studied using surface analysis techniques such as surface contact angle measurement. Pre-synthesized graft copolymers were added (5 phr) in styrene-acrylonitrile (SAN)/ethyl-ene-propylene-diene (EPDM) blends composition of 95/5 and 90/10. The adhesion parameters at the interface, that is work of adhesion, the interfacial energy and the coefficient of wetting were calculated and correlated to the differential scanning measurements measurements and SEM micrographs in order to study the effect of graft copolymers on compatibility of SAN/EPDM blends. It is obvious that depending of the graft copolymer's structure, various interactions between the components in the blend will be established, resulting in better adhesion which implicates improvement of compatibility in blends. Also, from the results, it can be seen that differences in structures of the added compatibilizer are clearly reflected in the adhesion parameters results, making this an acceptable method to determine whether two polymers are compatible. Morphology of the blends with the graft copolymers is significantly finer and the dispersed size is more uniformly distributed in comparison to the neat SAN/EPDM blend. The conditions of the optimal adhesion parameters with compatibilizer location at the interface, predicting by the thermodynamical models, correlated well with the improvement of the morphology and thermal measurements.