Abstract: This invention is directed to a thermoplastic polymer that is solid at room temperature and which expands on further polymerization, to form a crosslinked polymer, and to a process for preparing the polymer and the crosslinked polymer. In a preferred embodiment the polymer is prepared by polymerizing 10-90 but preferably 20-80 mole percent of a lower alkyl acrylic monomer containing a spirobislactone moiety, 10-90 but preferably 20-80 mole percent of a lower alkyl acrylic monomer containing an epoxide moiety, and 0.1-5 but preferably 0.5-1 mole percent of a lower alkyl acrylic monomer containing a functional moiety chosen from primary amino, secondary amino, mercaptan, and hydroxyl groups which can initiate crosslinking with the spirobislactone moiety. The crosslinked polymer is devoid of a spirobislactone carbonyl absorption band and is insoluble in conventional organic solvents.

Abstract: Bislactone curing agents are used to cure and copolymerize with epoxy-based esins. Preferably, the copolymerization is performed using a tertiary amine catalyst. During cure, the bislactone ring opens and expands. The use of bislactones as curing agents for epoxy-based resins avoids the shrinkage and accompanying stresses which occur when epoxy-based resins are cured conventionally. The novel bislactone cured epoxy-based polymers according the present invention are less prone to failure than are conventional epoxy-based polymers. In a further embodiment, the epoxy is copolymerized with a novel bislactone monomer having at least one trifluoromethyl group. The resulting fluorinated copolymer has a reduced surface energy.