Block and random copolyamides of poly(m‐xylylene adipamide) and poly(hexamethylene isophthalamide‐co‐terephthalamide): Methods of preparation and relationships between molecular structure and phase behavior

Abstract

Copolymerization of poly(m‐xylylene adipamide) (MXD6) and poly(hexamethylene isophthalamide‐co‐terephthalamide) (PA6I‐6T) was used as an efficient strategy to prepare amorphous homogeneous systems with improved properties mainly for packaging applications. The preparation of block copolymers was first of all tried by co‐extrusion of the two polymers and then by thermal treatments at high temperatures in DSC or mixing in Brabender, also in the presence of a catalyst. The occurrence of transamidation reactions led to macromolecular structures with different randomness degrees. Further, random copolymers, with the full range of compositions, were synthetized from monomers, by a fast and simple two‐stage melt polycondensation. For all the copolymers, the sequence distribution was studied by using a 1H NMR method developed by the Authors. The effects of preparation procedures, of mixing temperature and time, of the presence of a catalyst on the chemical structure, and, then, on final properties were studied. Interesting correlations among block length, monomer distribution and phase behavior were discussed. POLYM. ENG. SCI., SCI., 55:1475–1484, 2015. © 2014 Society of Plastics Engineers