Synthesis and characterization of poly(urethane-urea-acrylate)s

A series of relatively high molecular weight poly(ester-urethane-urea)s con taining pendant acrylate functionality was synthesized. Poly(ester-urethane -urea-acrylate)s were polymerized in a two step process: synthesis of an is ocyanate terminated prepolymers prepared from an excess molar concentration of 4,4'-methylene diphenyl diisocyanate with poly(ester)doils [Mn similar to 2000] and reaction of the product with hexamethylenediamine and neutrali zation with acrylic or metacrylic acid. These curable materials possess goo d mechanical properties and behave like common thermoplastic elastomers pri or to chemical crosslinking which further enhances their strength and insol ubilizes them. The cured materials were characterized by stress-strain, IR, and thermogravimetric experiments. It was found that the soft segment unit molecular weight was important in determining the tensile and thermal prop erties of this material. The crosslinking process depresses crystallization of the soft segments and improves tensile properties. Introducing diamine and acrylic structural units extends the hard urethane segments. (C) 1999 E lsevier Science Ltd. All rights reserved.