Mercapto-modified copolymers in polymer blends. II. The compatibilization of NBR/EVA blends

Ethylene-vinyl acetate (EVA) copolymer functionalized with mercapto groups (EVALSH) has been used as compatibilizing agent in nitrile rubber/EVA blend s. The tensile strength and elongation at break of the system were measured as a function of the EVALSH content and blend composition. The compatibili zation affects the mechanical properties of these blends. The highest impro vement of the tensile strength has been achieved in the composition range c orresponding to the co-continuous phase morphology. The co-continuity of th ese blends has been studied by both dissolution studies and scanning electr on microscopy. The addition of EVALSH as an interfacial modifier did not ch ange the region of co-continuity but influences the percolation threshold f or both dispersed nitrile rubber phase and dispersed EVA phase. From optica l microscopy and differential scanning calorimetry analysis, it is possible to assume that the functionalized EVALSH copolymer affects the crystalliza tion of the EVA phase. (C) 2000 John Wiley & Sons, Inc.