Advances in addition-cure phenolic resins

Recent developments in the area of addition curable phenolic resins are reviewed. The article highlights the chemistry of addition-cure phenolic resins and discusses the different strategies involved in their molecular design. Structural modification through incorporation of thermally stable, addition curable groups on the novolac backbone is one strategy. The transformation of phenolic hydroxyl groups to addition curable functions forms an alternate approach. Cross-linking of novolac or its derivatives with a suitable curative also leads to addition-curable phenolic resin systems. This article examines the synthesis, characterization and curing of noted addition curable phenolic systems. Their thermal, physical and mechanical properties are discussed and the structure-property correlations examined. In selected cases, the adhesive properties of the systems have been examined. The review includes discussions on the properties of the composites in relevant cases. The systems discussed here include mainly allyl- and maleimide-functional phenolics, epoxy-phenolic, polybenzoxazine, bisoxazoline-phenolic, acetylene-functional and propargyl ether phenolics and phenolic-triazine. The relative advantages and demerits of these systems are discussed and their application potentials are considered. (C) 2004 Elsevier Ltd. All rights reserved.