COMPATIBILIZED POLYMER BLENDS OF ISOTACTIC POLYPROPYLENE AND STYRENE-MALEIC ANHYDRIDE COPOLYMER

Compatibilized polymer blends of isotactic polypropylene, styrene-maleic anhydride copolymer (SMA) and two amino functionalized polyolefins-a rubbery amino functional ethylene propylene copolymer and an amino functional isotactic polypropylene-have been formulated over a wide composition range. Blends containing approximately 25% SMA have a morphology that consists of a continuous polyolefin matrix with a dispersed phase of micrometre-sized SMA particles. The amino polyolefins are believed to form graft polymers with SMA by an amidation reaction with the maleic anhydride. The blends have bulk properties such as impact strength and solvent resistance similar to polypropylene; however, their surface reactivity (e.g. adhesion of paint and polar substrates) is similar to that of SMA. The rheology of these blends is complex but typical of immiscible polymer blend systems.