BLENDS OF POLYAMIDE-6 AND BISPHENOL-A POLYCARBONATE - EFFECTS OF INTERCHANGE REACTIONS ON MORPHOLOGY AND MECHANICAL-PROPERTIES

Blends of polyamide 6 (PA6) and polycarbonate (PC) were prepared in a Brabender mixer, at 240-degrees-C, applying long mixing time, for 45 min. It was observed that the morphology and the mechanical properties tend to resemble those of a homogeneous material as the mixing time and PA6 concentration increase. This is attributed to chemical reactions taking place between the two homopolymers. Acidolysis, amidolysis, and aminolysis, catalyzed by the terminals and the amide groups of the polyamide, should in principle be possible. Our results indicate that the aminolysis is the main process, inducing simultaneously scission of PC chains and formation of PC-PA6 copolymer chains. The latter act as interfacial agents between incompatible PA6 and PC, improving the mechanical properties of PA6-rich blends, in agreement with the predictions of some theoretical models assuming good phase interpenetration.