HIGH-RESOLUTION C-13 NUCLEAR-MAGNETIC-RESONANCE STUDIES OF AN UNSATURATED POLYESTER IN THE SOLID-STATE

Unsaturated resins crosslinked with styrene, have been investigated by magic angle spinning-cross polarization (MAS-CP) **1**3C nmr and relaxation times in the rotating frame obtained. The relaxation times T//1// rho obtained ranged from 2 to 34 ms, and were found to change with cure temperature in the polyester resin with a maximum value observed for all carbons when curing proceeded in the temperature region 80 degree C-90 degree C. The relaxation times evaluated indicate that more complete crosslinking occurs at temperatures in this temperature region indicating that there was a correlation between T//1// rho and the cure temperature. This influence on the molecular mobility is dependent on the carbon chain polymer length and thereby on the number of endgroups in the carbon chain polymer.