UV generation of a multifunctional hyperbranched thermal crosslinker to cure epoxy resins

A new hyperbranched polymer (HBP) was obtained via an iterative synthetic procedure that consists of esterification and thiol-ene click reaction. This polymer was used as a latent multifunctional macroinitiator for the dual curing of a commercially available cycloaliphatic epoxy resin and this process was studied by photo-DSC and FTIR. The presence of thioether groups in the HBP structure leads, by photoirradiation, to the formation of sulfonium salts, which are thermal cationic initiating species. The materials obtained were characterized by DMTA, TGA, gel content and FESEM. By means of the last technique domains of HBP as a second phase within the epoxy matrix were observed.