SOLUTION AND SOLID C-13 NMR-STUDIES OF MULTIFUNCTIONAL POLYOLACRYLATENETWORKS

Several C-13 NMR techniques are introduced to address the problem of s tructure determination of photopolymerized polyolacrylates, and to stu dy both the liquid and solid states of acrylic monomers and oligomers, as well as the network structure formed upon their photopolymerizatio n. By measuring the relative integration of specific peaks in the carb on spectra as a function of the time of irradiation and laser power, t he relative reactivity of monomers/oligomers used in the early stages of polymerization is determined. Changes in crosslink density and in t he mobility of the polymeric chains can be followed throughout the pho topolymerization process by monitoring proton T-1 rho relaxation times . The degree of crosslinking is correlated to the relaxation times and it increases with an increasing power of the irradiating laser even u nder conditions where the degree of conversion, as measured by quantit ative infrared absorption of the 810 cm(-1) band of the acrylate is al most unchanged.