Cationic Polymerization of Benzoxazine Monomers by Boron Trifluoride Complex

Abstract

Purified monofunctional benzoxazine monomers have very low reactivity, and some of them do not polymerize at all after several hours using the usual thermally initiated method. In this work a boron trifluoride complex with water was used to initiate the polymerization of some of the monofunctional benzoxazine monomers that do not polymerize when heated. The reactions were studied by Fourier transform infrared spectroscopy. The influence of the amine basicity on reactivity was investigated as well as the behavior of a bifunctional monomer. A new proposition for the benzoxazine polymerization mechanism, based on the experimental data, is discussed.