POLY(PHENYLENE OXIDE) POLYAMIDE BLENDS VIA REACTIVE EXTRUSION

Reactive extrusion of functionalized polymers provides a convenient, commercially attractive route for the preparation of copolymers useful in compatibilization of polymer blends. In the current study, the grafting chemistry of maleic anhydride to poly(phenylene oxide) in the absence of a radical initiator is contrasted to that of efficient quinone‐methide trapping agents such as maleimides. In the case of maleic anhydride, functionalization is shown to occur randomly along the polymer backbone whereas maleimides react to give both main chain and end‐group derivatives. Use of this anhydride‐functionalized polyfphenylene oxide and an end‐group functionalized analog in blends with polyamide‐6,6 affords high levels of graft and diblock copolymers respectively, sufficient for the preparation of highly ductile materials. The properties of these polyamide blends are found to depend on the amount of copolymer formed during extrusion with final copolymer levels being in turn returned to the degree of anhydride functionalization. The properties and morphology of blends containing graft or diblock copolymers derived from main‐chain and end‐group functionality respectively, are rationalized in terms of the relative effectiveness of different copolymer structures in blend compatibilization. Copyright © 1990 Society of Plastics Engineers