Poly(oxypropylene)-amide grafted polypropylene as novel compatibilizer forPP and PA6 blends

Poly(oxypropylene)-amide grafted polypropylene (PP) was prepared in an extr uder by the reaction of poly(oxypropylene) (POP)diamines and maleated PP (P P-g-MA). The resulting POP-grafted PP copolymers are confirmed by the FTIR analysis, and used as compatibilizers for polyamide 6 (PA6) and polypropyle ne blends, These compatibilizers, POP-functionalized PPs (PP-g-MA-co-POPs), have different amphiphilic properties depending on the content of MA in th e starting PP-g-MA and the molar ratio of MA/amine. The compatibilization e ffect is examined in terms of morphologies, thermal and mechanical properti es. The morphologies, affected by the molecular weight of POP diamine in PP -g-MA-co-POP copolymer, show a decreasing size of the dispersed PA6 particl es as the molecular weight of POP diamine increasing from 230 to 400 to 200 0. Using these PP-g-MA-co-POP copolymers, the compatibilized blends show im provements in mechanical properties, including Izod impact strength and ten sile toughness, over a conventional compatibilizer. The POP and amide funct ionalities in the compatibilizers can facilitate the formation of hydrogen bonding with PA6 and, therefore, the compatibilizing effect. During the com pounding process, the compatibilizers further react with PA6 in situ to aff ord the mixture of PP-g-MA-co-POP-PA6, PP-g-MA-co-POP-co-PA6 and PP-g-MA-co -PA6 copolymers, which further improves the compatibilizing effect. (C) 200 0 Elsevier Science Ltd. All rights reserved.