Synthesis and characterization of radiation curable polyurethanes containing pendant acrylate groups

Abstract

AbstractA series of radiation sensitive and relatively high molecular weight poly(tetramethylene adipate) polyurethanes containing pendant acryfate functionality was synthesized. These radiation curable materials possess good mechanical properties and behave like common thermoplastic elastomers prior to chemical crosslinking which further enhances their strength and insolublizes them. Both the precursor and the cured materials were characterized by stress‐strain, differential scanning calorimetry. and dynamic mechanical testing. It was found that the poly‐(tetramethylene adipate) soft segments with molecular weight of 2000 or higher were crystallizable in the cross‐linked network. The soft segment molecular weight and the diisocyanate type were found to be important in determining the tensile and thermal properties of these male‐rials. The crosslinking process was found to depress crystallization of the soft segments and to improve tensile properties. Increasing the soft segment molecular weight resulted in an Increased elongation al break bill a decreased ultimate stress for both the precursor linear polymers and the crosslinked materials.