POLYMERS WITH PENDANT CYANATE ESTER GROUPS - SYNTHESIS, THERMAL CURING AND PHOTO-CROSS-LINKING

The new monomers 4-vinylphenyl cyanate and 2,6-dimethyl-4-vinylphenyl cyanate were prepared from 4-hydroxyacetophenone and 3,5-dimethyl-4-hy droxyacetophenone as starting materials. The styrene copolymers of the cyanate ester monomers were prepared via free radical polymerization. The copolymers were sensitive to UV light and became crosslinked afte r irradiation with 254 nm light. The cyanate ester groups in the copol ymer of 2,6-dimethyl-4-vinylphenyl cyanate isomerized to isocyanate gr oups during UV irradiation. Thermal curing of the copolymers with 4-no nylphenol as catalyst yielded networks containing cyanurate groups. (C ) 1998 Elsevier Science Ltd. All rights reserved.