Physical properties and shrinkage of epoxy resins cured with lactams

In order to reduce the shrinkage of epoxy resin during the curing process, lactam is incorporated into epoxy in a copolymerization reaction. In this study, various amounts of lactams and BF₃-MEA were added to epoxy, and the volume shrinkage of polymerization was investigated. It was found that shrinkage decreases with the increase of the lactam content and with the lactam ring size as well. Infrared spectroscopic analysis, scanning electronic microscopic analysis, and mechanical tests were used to investigate the structure and properties of the copolymers. The results show that the incorporation of caprolactam leads to an increase in tensile strength and elongation, but the Izod impact strength is not improved.