Properties Enhancement Obtained in Anhydride-Modified Polybenzoxazines: Effects of Ester Functional Group on Polybenzoxazine Network

Abstract

Ring-opening polymerization of benzoxazine resin is a relatively clean chemistry. The reaction provides a polybenzoxazine network without releasing any by-product that might cause defects or voids in a fully cured polymer. The network formation of the resin is also known to provide very useful functional groups, such as phenolic moieties. This phenolic functional group enables further modification of the polybenzoxazine to yield a broader range of attractive properties through copolymerization, alloying, or composite formation, etc. In this chapter, we demonstrate this uniquely outstanding characteristic of benzoxazine resin to form copolymers with various kinds of acid anhydrides. The interaction between the resin and anhydride has been demonstrated through a formation of ester linkages. The chemistry of this interaction is very simple, highly cost-competitive, and yields copolymer products with excellent improvement in the thermal and mechanical properties, including more than 80oC enhancement on glass transition temperature and thermal degradation temperature, a more than 2.5-fold increase in char yield and substantial improvement in flexibility of the obtained copolymer films. Thus, the anhydride modification of polybenzoxazine is a highly practical measure to enhance polybenzoxazine properties and is very attractive for industrial use. © 2017 Elsevier Inc. All rights reserved.