Abstract
The dipolar-decoupled, natural abundans Fourier transform and cross-polarization C13-NMR spectra of epoxy resins have been obtained at 15 MHz, with about 2 KHz mechanical spinning at the magic angle.
It is shown that 1H rotating-frame spin-lattice relaxation time constant (TH1ρ) is most usable. in monitoring the curing process of epoxy resins, especially at the first stage.
The TH1ρ due to aromatic carbons decreases in accordance with degree of cure.
Values of both Tg and TH1ρ of cured resins at the final stage are various by curing temperature.
