Abstract
We attempted to improve the thermostability of thermosetting resins by controlling cross-linking structures with living radical polymerization. It was found that the thermal decomposition- and glass-trasition-temperature (Tg) of the resin cured by alkylboranes as living radical initiator were higher than those of the resin cured by typical radical initiators such as peroxides or azo compounds. In this study, in order to reveal the relation between Tg and cross-linking structure, resin controlled cross-linking structures were synthesized with the rate of polymerization constants (k_p) and the resin were evaluated by solid state NMR. In the solid state NMR, ^<13>C-NMR spectra and spin-lattice relaxation times (T_<1p>) were measured. T_<1p> value of the resin controlled cross-linking structures was shorter than those of typical resins, that implies the controlled resin had more ordered structure compared with typical resins. These results suggest the solid state NMR is effective for the analysis of cross-linking structure of thermoset resins.
