Process for preparing semi-aromatic copolyamides and copolyester-amides.

摘要

Semi-aromatic copolyamides and copolyester-amides are obtained by placing an aliphatic polyamide into contact with an aromatic hydroxyacid or aminoacid, by operating at high temperature, under melting conditions, possibly in the presence of a catalyst, with a ratio of the monomer units of aliphatic polyamide to the mols of aromatic hydroxyacid or aminoacid comprised within the range of from 20:1 to 1:1. The semiaromatic copolyamides and copolyester-amides so obtained can display a thermotropic liquid-crystal behaviour as a function of their content of aromatic units linked inside the molecular chain. Their elastic modulus results to be improved relatively to the alifatic polyamides used as the starting product, and the elongation at break results to be decreased. Such semiaromatic polyamides and copolyester-amides can find application in the production of high-stiffness articles, by means of moulding or extrusion processes. They can also be used as blends with the usual thermoplastic polymers, in which they act as reinforcer or compatibilizer agents.