Modification of polymer melts by oxazolines and their use for interfacial coupling reactions with other functional polymers

The blending of immiscible polymers offers attractive opportunities for developing new materials with useful combinations of properties [1–5]. However, most blends are immiscible and often have poor mechanical properties and unstable morphologies. Compatibilization of such blends is necessary. Preformed block or graft copolymers have been traditionally added to polymer blends as compatibilizers [6, 7]. However, owing to the lack of economically viable routes for the synthesis of suitable copolymers for important blend systems, compatibilization by preformed copolymers has not been used as extensively as the potential utility might suggest. A more proactive alternative is to generate these copolymers in situ during the melt blending of suitably functionalized polymers [8, 9]. In situ reactive compatibilization has already been implemented in a number of commercial products. One of the well-known examples is Du Pont’s super tough nylons, where maleic anhydride (MA) is first grafted onto poly(ethylene-co-propylene-co-diene) (EPDM) rubbers and then reacted with the terminal amine groups of nylons. A number of other engineering polymers have followed with similar compatibilization strategies.