Abstract
Solid-state CP/MAS (Cross Polarization/Magic Angle Spinning) -13C-NMR spectroscopy was applied to the analysis of the curing reaction of the blends of maleimide resin, which formed from bismaleimide and aromatic diamine, and epoxy resin.
In CP/MAS-13C-NMR spectra of maleimide-epoxy resin blends, the peak at 170ppm was attributed to conjugated carbonyl carbon of unreacted maleimide, and the peak at 176ppm was non conjugated carbonyl carbon of reacted maleimide, and the peak at 52ppm was methyne carbon of epoxy groups. The reaction processes of maleimide and epoxy groups can be followed by estimating relative intensity of the three peaks.
In curing reaction of maleimide-epoxy resin blends without catalyst, the addition reaction of amino groups to epoxy groups occurred mainly, and the reaction of maleimide proceeded slowly at 170°C. The polymerization of maleimide and the addition reaction of secondary amine to epoxy groups occurred on post curing at 200°C.
In the presence of imidazole catalyst, the polymerization of maleimide proceeded rapidly, but the polymerization of epoxy groups hardly occurred at 170°C. The polymerization of epoxy groups occurred on post curing at 200°C.
