A new epoxy/episulfide resin system for coating applications: curing mechanism and properties

A new epoxy/episulfide resin was applied using a polyamide(V-40((R))) curin g agent system. The epoxy/episulfide/V-40((R)) system exhibits much faster cure, better corrosion protection for copper, a lower thermal expansion coe fficient and lower exotherm as compared with standard amine cure, room-temp erature epoxy systems. From model compound studies, episulfide-amine, S--ep oxy, epoxy-amine reactions and episulfide homopolymerization proceed in the epoxy/episulfide system. The curing reactions are changed by changing the curing temperature and by the presence of copper. The episulfide homopolyme rization and the S--epoxy reaction increase in the case of room-temperature curing or in the presence of copper. The episulfide and/or the S- react wi th copper. From DSC measurements, the resin near the copper surface has hig her T-g than the bulk resin due to the fact that the episulfide tends to po lymerize near the copper surface. (C) 2000 Elsevier Science Ltd. All rights reserved.