CONTENTS 3 Entropy Elasticity

The aim of any grafting is to increase the rubber efficiency, i.e. the ratio between the gel content and the rubber content, and to enable the rubber particles to bond to the polystyrene phase in order to ensure the transmission of external forces from the energy-elastic phase to the entropy-elastic phase. The graft polymer acts as emulsifier and stabilizes the dispersed rubber particles in the two-phase system. 

Engelmann s principal findings are presented in Figs 10 and 11. With test methods which respond to the material s entropy elasticity, the acrylonitrile content of the NBR and the type and amount of plasticiser exert a decisive influence. With test methods which determine toughness and brittleness characteristics at low temperatures, the rubber-filler interactions are important where polymer blends (e.g. NBR/BR) are concerned, the morphology, too, plays a decisive part ... 

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