Miscibility and physical properties of blends of poly(styrene-co-acrylonitrile) with flame retardant tetrabromobisphenol A-epoxy

We investigated miscibility and physical properties of blends of poly(styrene-co-acrylonitrile)s (SANs) having different copolymer compositions with flame retardant chemicals (tetrabromobisphenol A-epoxy's (TBA-EPs)). Miscibility of the blends was judged from the light transmittance. TBA-EP having molecular weight of 1300 was miscible with SANs having 20 to 30 wt% of acrylonitrile content and 7.7 similar to 12.8 X 10(4) of molecular weight. The glass transition temperature and viscosity of the blends decreased with an increase in the TBA-EP content owing to the plasticizing effect. On the other hand, TBA-EPs having molecular weight of 10000 and above were immiscible with all SAN samples used in this study. Mechanical properties of the blends deteriorated on blending of the TBA-EPs having molecular weight of 10000 and 20000, but not on blending of the TBA-EP having higher molecular weight because of its higher mechanical properties. Copolymer composition of resins and molecular weight of flame retardant chemicals were found to be important key factors to develop flame retardant styrenics resins.