Interface entre polymères semi-cristallins renforcées par des copolymères diblocs

The interface between isotactic polypropylene (iPP) and polyamide 6 (PA6) was studied. We used functionalized: polypropylenes (PPf) able to react with PA6 as compatibilizing agents. The copolymer formation allows the stabilization of the interface and the study of its crystalline orientation. The amount of copolymers at the interface, Sigma, was measured by XPS. The copolymer formation kinetics were thus determined and we show that it strongly depends on the PPf structure. The mechanical strength of the interface, G(c), was-also measured, as a function of the annealing temperature and PPf structure. The coupling between G(c) and Sigma measurements allowed us to determine the reinforcement mechanisms of the interface. We show that the efficiency of high molecular weight copolymers is maximum for annealing temperatures above the melting temperatures of both matrices, whatever the microstructure. This effect is related to the ability of the copolymers to bridge several crystalline lamellae in the epitaxially oriented layer at the interface.