Recent Development of Polybenzoxazine Aiming for High Performance Network Polymer

Abstract

Polybenzoxazine is a novel type of phenolic resin obtained by the ring-opening polymerization of benzoxazine, which is easily prepared from phenols, primary amines, and formaldehyde. The versatile molecular design is a strong point of benzoxazine resin, and the properties of the cured resin can be manipulated easily and widely. Very often, the presence of phenolic hydroxyl group and intra- and inter-molecular hydrogen bonding is the key for the molecular design that lead to the cured resin having unique properties. The thermal properties can be easily improved by various approaches including the addition of crosslinkable units, the increase of rigidity, and the addition of fillers. The toughness is also improved by polymer alloying, by copolymerization with various monomers, and by the approach of high molecular weight benzoxazines. It is very interesting that the approach to enhance the toughness of polybenzoxazine very often improve the thermal properties. Preparation of functional polybenzoxazines is also ongoing by various approaches. Polybenzoxazine is currently being interested as a highly value-added novel resin. The achievement of shortening the curing time and lowering the curing temperature is expected to widen the application field to great extent.