Morphology and rheological behavior of amorphous polyamide/(styrene-acrylonitrile/styrene maleic anhydride) reactive blends

The effects of styrene maleic anhydride (SMA) random copolymer on the morphology and rheological behavior of amorphous polyamide/styrene-acrylonitrile (SAN) copolymer blends have been investigated. The anhydride group in SMA can react with the amine group in polyamide to form in situ graft copolymers at the polyamide/SAN interfaces during the melt blending. The extent of reaction was assessed by the torque change with time in the mixer. The torque obtained from a torque rheometer was compensated using a reference temperature since the actual temperature in the mixer was higher than the setting temperature due to viscous heating and exothermic reaction. The compensated torque data were found to be very useful to study the extent of reaction between functional groups during melt blending of reactive blend system, especially in the case of small concentration of Functional groups available to reaction. Morphological observation showed that the finer dispersion of the SAN domains with rather narrow distribution was obtained when SMA was added to the blend.