RADIATION ASSISTED COMPATIBILISATION OF BLENDS OF VINYLIDENEFLUORIDE POLYMERS WITH FLUOROSILICONE ELASTOMERS BY MEANS OF CROSS-LINKING COAGENTS

An experimental study was carried out to demonstrate the possibility o f compatibilising blends of polyvinylidenefluoride with minor amounts of fluorosilicone elastomer, thereby achieving better low temperature ductility without excessively reducing the melting point and degree of crystallinity of the fluoropolymer. The principle that has been explo red is the use of multifunctional crosslinking agents acting as a comm on solvent for the two polymers during mixing, and providing interpene trating networks through the two polymer phases by means of peroxide-i nduced crosslinking reactions. It has been found that mixtures of tria llyl isocyanurate with diallyl phthalate are particularly effective in compatibilising the combination of polymers in question, giving the b est overall balance of properties. Compatibilisation was enhanced by g rafting part of the coagent on to the chains of the fluoropolymer prio r to being blended with the fluorosilicone gum. Further evidence for e nhanced compatibilisation by such a procedure was obtained from dynami c mechanical tests, which revealed an increase in glass transition tem perature for the fluorosilicone phase and a suppression of alpha-relax ations in the fluoropolymer component.