Poly( m -xylylene adipamide)-based Copolyamides: Effect of the Chemical Structure on Oxygen Permeation Properties

Poly(m-xylylene adipamide) (MXD6) is a well-known polyamide, widely used in engineering applications for a favourable set of mechanical properties and in packaging materials manufacturing because of its excellent gas barrier properties. In this work new random copolymers based on MXD6 were prepared by melt polycondensation of different comonomers (diacids and diamines) together with m-xylylene diamine and adipic acid with the aim of studying the effect of various chemical structures on the final barrier properties and trying to improve barrier performances of MXD6 at high humidity level. The resulting copolyamides were characterized in order to investigate the structureproperty relationships. Attention has been focused on the changes in glass transition temperature, density, sub-Tg relaxations. Interesting correlations between structure and oxygen permeation properties have been found.