Synthesis and Characteristics of Radiation Curable Polyurethanes Containing Pendant Acrylate Groups

摘要

A series of radiation sensitive and relatively high molecular weight polytetramethyleneadipate polyurethanes containing pendant acrylate 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 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 polytetramethylene adipate soft segments with molecular weight of 2000 or higher were crystallizable in the crosslinked network. The soft segment molecular weight and the diisocyanate type were found to be important in determining the tensile and thermal properties of these materials. 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 at break but a decreased ultimate stress for both the precursor linear polymers and the crosskinked materials.