High Performance Polybenzoxazines as Novel Thermosets

Abstract

Polybenzoxazine as a novel phenolic type thermoset has been developed to overcome the shortcomings associated with the use of the traditional phenolics. It can be prepared from cyclic benzoxazines via thermally induced ring-opening polymerization. Various benzoxazine monomers can be synthesized from mono-or diamines and mono-or bisphenols with formaldehyde. Polybenzoxazines have not only the advantageous properties of conventional phenolic resins such as high thermal properties, but also other interesting advantages that are not found in the traditional phenolic resins such as excellent dimensional stability. The disadvantages of the typical polybenzoxazines are the high temperature needed for complete cure and the brittleness of the cured materials. Further improvement of thermal properties is also expected for application in harsh conditions. Herein we report on various approaches for performance improvement of polybenzoxazine. These approaches include alloying with other high performance polymers, hybridization with inorganics, and designing of novel monomers as well as high molecular weight polymeric precursors. By these approaches, lowering of the cure temperature, improvement of toughness, and enhancement of thermal and mechanical properties were achieved.