Applications of polybenzoxazines for improvement in processability and property

Polybenzoxazines obtained from the polymerization of benzoxazine monomers or oligomers has been used for various applications: to simplify the technology adopted for protection, to improve the processability of high performance material and to replace the environmental hazards in resins.;Novel siloxane-containing benzoxazine oligomers with benzoxazine rings in the main chain have been synthesized and mixed with octasilane polyhedral silsesquioxane (OctaSilane POSS) and glass sphere to form a thermo-oxidatively stable coating on a carbon/carbon composite after polymerization and baking. The coating method is very simple and inexpensive compared with the conventional approaches, such as chemical vapor deposition. The effectiveness of the coating has also been demonstrated.;A new class of benzoxazine-containing monomers, namely bis(benzoxazinemaleimide) s have been synthesized to improve the poor processability of bismaleimides. A new approach of using high boiling point nonpolar solvent has been developed to prepare the monomer, which is difficult to synthesize using the traditional method of synthesizing benzoxazines. In the meantime, by the combination of two types of polymers: benzoxazine and bismaleimides, high thermally stable thermosets with high Tg have been obtained.;Benzoxazine monomers have also been introduced into vinyl ester resins to replace styrene for environmental concern. With the incorporation of allyl-containing benzoxazines, the dynamic mechanical property and the thermal stability of the resins have been improved, while the processability of the resin is maintained.