PHASE-BEHAVIOR OF POLYAMIDE-POLYESTER BLENDS - THE INFLUENCE OF AROMATICITY

Miscibility in blends of semi-aromatic polyamides and random aliphatic co-polyesteramides, derived from epsilon-caprolactam, epsilon-caprola ctone and laurolactam has been investigated by calorimetric methods. D ilution of epsilon-caprolactam by epsilon-caprolactone in PA-6 transfo rms miscible blends based on PA-6I and PA-TMDT, respectively, to immis cible mixtures at approximately 35 and 46 mol%, respectively, of epsil on-caprolactone in the copolymer. The data have been found to conform to an analysis provided by a binary interaction model incorporating se gmental interaction parameters, chi(ij), derived from related blends. Extension of the treatment to polyamide/polyester blends whose constit uents contain aromaticity, e.g. PA-66/poly(ethylene terephthalate), PE T and PA-6I/polyarylate, PAr, has also been explored. The results conf irm the gross immiscibility, indicated by a large unfavourable interac tion parameter, typically encountered in these blends. (C) 1997 Elsevi er Science Ltd.