MICROSTRUCTURE EFFECTS ON ADHESION AT POLYPROPYLENE/POLYAMIDE 6 INTERFACES

摘要

Experiments on thin films have shown an epitaxy relationship between iPP and PA6 on the one hand and between sPP and PA6 on the other hand. Both of them are influenced by the same factors as the adhesion energy of macroscopic joints. We tried to elucidate the role played by the copolymer and by the interfacial organization in the adhesion reinforcement. We achieved this by varying the composition and microstructure of the functionalized chains and hence their miscibility with the matrix. Strong microstructure effects appear on the kinetics of formation of the copoly-mers and of adhesion enhancement, the kinetics being much faster when the matrix and the PP block have closely matched microstructures. Besides, the copolymer efficiency is higher when the PP block is of high molecular weight, and particularly for high annealing temperatures. We related that effect to a synergy between the ability of the copolymers to connect crystalline lamellae and the increase of the crystalline orientation of the interface.