engleski

Surface phenomena in SAN/EPDM blends

In immiscible polymer blends such as styrene-acrylonitrile (SAN)/ethylene-propylene-diene (EPDM) interactions (adhesion) between phases is poor and requires surface modification, which can be accomplished by various modifiers. Block or graft copolymers whose segments are chemically identical or having affinity with the polymer components are often used as interfacial modifiers (compatibilizers) to reduce the interfacial tension, promote the dispersion of one phase in another and stabilize resulting blends. A series of four different types (different structures) of ethylene-polypropylene-diene-graft-polystyrene (EPDM-g-PS) copolymers were synthesized and their surface property variations were studied using surface analysis technique such as surface contact angle measurement. Pre-synthesized graft copolymers were added (5 phr) in styrene-acrylonitrile (SAN)/ethylene-propylene-diene (EPDM) blends composition 95/5 and 90/10. By determination of parameters of adhesion (surface free energy, work of adhesion, coefficient of wetting), the effect of surface restructuring of the blend components was studied. From the results it can be concluded that depending on graft copolymers structure, various interactions between the components in blend will be established, resulting in restructuring and various orientations of components in blend surface.

Surface phenomena; polymer blends; miscibility

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