Photothermal polymerization of benzoxazines

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.