Photothermal polymerization of benzoxazines

Abstract

Despite the use of catalysts and initiators, high polymerization temperatures are typically required for polybenzoxazines, a severe constraint for their general application as high performance thermosets. In this work we pioneer a novel photothermal strategy for the synthesis of polybenzoxazines that takes places under light irradiation at ambient conditions. This method capitalizes on the intriguing optical properties of benzoxazine–catalyst systems, which show visible light absorption and locally generate large heat upon illumination that triggers polymerization. In this way a large variety of benzoxazine monomers can be converted into polymer materials that retain some of the relevant features of polybenzoxazines – e.g., high char yields. In addition, our photothermal approach allows spatial control of benzoxazine polymerization, which we exploit for the fabrication of polybenzoxazine patterns via photolithography.