EFFECT OF ADDITIVES ON IMPACT POLYVINYL-CHLORIDE)

The two‐phase nature of a graft copolymer of ethylenepropylene‐1:4 hexadiene (EPDM) and poly(vinyl chloride) (PVC) has been established by dynamic mechanical measurements. The interaction of different additives with the isolated graft copolymer has also been inferred from their dynamic mechanical and thermal properties. Carbon black and titanium dioxide act as inert filler, while the effect of including straight‐chain hydrocarbons (e.g., n‐hexadecane and n‐hexatriacontane) is strongly dependent upon the melting point of the hydrocarbons. Sunflex 110 plasticizes the rubber phase of the graft copolymer while dioctyl (di‐2‐ethyl hexyl) phthalate (DOP) plasticizes the PVC phase and reduces Tg. At lower temperatures, however, the elastic modulus is increased by an “antiplasticization” effect. The local environment of PVC chains in the graft copolymer is modified by the presence of the rubber and PVC chains are less mobile. Copyright © 1979 John Wiley & Sons, Inc.