Synthesis, Polymerization Kinetics of 4-Allyl-substituted 1,3-Benzoxazine and Properties of Resulting Polymer

In this paper, a novel 4-allyl-substituted 1,3-benzoxazine (P-a-[4]ally) was successfully synthesized based on the allylation reaction of aldimines. The chemical structures of intermediates (P-1 and P-2) and P-a-[4]ally were characterized by NMR spectra, and Fourier transform infrared (FT-IR) spectra. The polymerization and curing kinetics were studied by DSC and in-situ FT-IR, and the charge densities of atoms were calculated by Materials Studio. The activation energy of the curing reaction was 108.3 kJ.mol(-1) by the Kissinger-Akahira-Sunose method and 111.0 kJ.mol(-1) by the Ozawa method. Thermomechanical analysis (TMA), thermogravimetric analysis (TGA), and an Agilent impedance analyzer were used to investigate the thermal and dielectric properties of poly-benzoxazine (P(P-a-[4]ally)). The results revealed that the glass transition temperature (T-g) of P(P-a-[4]ally) was 154 degrees C, the temperature at 5% weight loss (T-d,T-5%) was 329 degrees C, the char yield was 21.2% at 800 degrees C under N-2, and the dielectric constant was 3.33 at 1 MHz.