C. Lin, Y. S. Shih, M. Wang
Apr 1, 2014
Citations
0
Influential Citations
18
Citations
Journal
Polymer
Abstract
Abstract A pyridinyl-containing benzoxazine ( 6 ) was synthesized from the Mannich condensation of 4-phenyl-2,6-bis(4-aminophenyl) pyridine ( 2 ), phenol, and paraformaldehyde. For the purpose of properties comparison, a benzoxazine ( 7 ), which is structurally similar to ( 6 ) except for the pyridinyl group, was prepared. The solvent effect on the synthesis of ( 6 ) was discussed, and toluene/ethanol was found to provide ( 6 ) with the best purity and yield. The pyridinyl group provides solubility and acts as a catalyst for the ring opening of benzoxazine, as supported by the forward curing in the DSC thermograms. When curing with epoxy resins, a carbonyl absorption at 1670 cm −1 and 192 ppm was observed in the IR and 13 C NMR spectra. It is proposed that the formation a cyclic amide structure is responsible for the absorption. A reaction mechanism including nucleophilic addition, Diels–Alder reaction, and rearrangement was proposed. The pyridinyl group acts as a crosslinking site, and results in thermosets with good thermal properties.