DYNAMIC-MECHANICAL PROPERTIES AND CROSS-POLARIZED, PROTON-ENHANCED, MAGIC-ANGLE-SPINNING C-13-NMR TIME CONSTANTS OF URETHANE ACRYLATES .1. HOMOPOLYMER NETWORKS

Dynamic-mechanical properties have been measured for a series of ureth ane acrylates containing polyether and polyester soft segments. Polyme r glass transition temperatures predicted from a crosslinking relation showed better agreement with experimental T(g) values than those obta ined from applying the Fox equation to hard and soft segments in the p olymer. Proton-enhanced, magic angle spinning C-13-NMR time constants were obtained for a polyether soft segment urethane acrylate series. I ncreasing soft segment molecular weight resulted in a release of both near static and high frequency (mid-kHz) components of motion in the s oft segment.