SYNTHESIS AND CHARACTERIZATION OF POLYFUNCTIONAL CROSS-LINKING AGENTSFOR CYANATE RESINS

An efficient crosslinking monomer for a mixed cyanate/epoxy resin syst em, bisphenol-A-monocyanate monoglycidyl ether 3, has been synthesized and characterized. The intermediate compound, the monoglycidyl ether of bisphenol-A 2, was also isolated and purified by extraction and chr omatographic separation using a silica gel column. The cyanate functio nal group in the crosslinking monomer 3 can be cured easily by heat to form a triazine structure 8, but the epoxy functional group in the cr osslinking monomer 3 can not be cured without affecting the cyanate gr oup because the latter is more reactive both under heat and basic cond itions. A practical approach for the application of the crosslinking m onomer 3 is discussed and tested. Most interestingly, under heat curin g, a very tough and strong resin material was produced from this cross linking mixed resin mixture. By using a secondary amine, diethylamine, as a curing agent, the cyanate groups in the crosslinking monomer 3 r eact to form the structures 11 or 12, depending on the molar ratio of monomer 3 to diethylamine. A bifunctional crosslinking agent for a mix ed cyanate (thermoset) and polyolefin (thermoplastic) resin system, 8- allylphenyl cyanate 16, has also been synthesized and characterized. L ike 3, 2-allylphenyl cyanate 16 easily forms the crosslinking triazine compound 17 upon heating. 17 is a crystalline solid with mp = 110-111 degrees C. As a crosslinking agent, 8-allylphenyl cyanate 16 reacts n ot only with itself, but also with other cyanates to form heterogeneou s triazine rings, exemplified by triazines 18 and 19. Even though it d oes not self polymerize through the allyl double bond, it can copolyme rize with an other olefinic monomer, such as methyl methacrylate, to f orm a crosslinked and insoluble polymer. (C) 1995 John Wiley and Sons, Inc.