REACTIVE BLENDING OF POLY(STYRENE-CO-MALEIC ANHYDRIDE) WITH POLY(PHENYLENE OXIDE) BY ADDITION OF ALPHA-AMINO-POLYSTYRENE

Alpha-(3-Aminopropyl-1-amino)polystyrene (alpha-amino-PS) was melt-ble nded with styrene/maleic anhydride copolymers (SMA) containing 28 wt% maleic anhydride groups. The terminal primary amino group can react wi th the maleic anhydride monomer units in SMA, forming imides. The resu lting product turned out to be an efficient emulsifier for SMA blends with poly(phenylene oxide) (PPO). At constant weight fraction of added alpha-amino-PS, the size of the dispersed PPO particles decreased wit h decreasing molar mass, i.e. increasing mole fraction, of the alpha-a mino-PS. In a second series of experiments, alpha-amino-PS with M(n)BA R > M(entanglement)BAR, was used to compatibilize SMA/PPO blends which also contained poly(acrylonitrile-co-butadiene-co-styrene) and some p oly[styrene-b-(ethylene-co-butylene)-b-styrene] triblock copolymer. Al though, in this case, it was not possible to detect major changes in t he phase texture or morphology, it could be shown that the addition of alpha-amino-PS improved the impact strength significantly. For compar ison, blends were also prepared with unmodified PS of a similar M(n)BA R. No corresponding improvement of the mechanical properties was obser ved in this case.