Controlled Oxidation of a Tetrafunctional Thiol to Obtain a Poly (Thiol- disulfide) Oligomer and Its Use as Self-healing Agent for Epoxy/Thiol-ene Photocurable Systems | Chapter 02 | New Advances in Materials Science and Engineering Vol. 2
In this work the pentaerythritol tetrakis (3-mercaptopropionate) was partially oxidized to obtain an oligomer with both thiol and disulfide functional groups in its structure, by using iodobenzene diacetate (IBDA) as oxidant. This oligomer was used to introduce disulfide bonds into the crosslinked network of a polyether-polythioether matrix obtained by photopolymerizing an epoxy/thiol-ene system. The presence of the disulfide bonds induced self-healing properties bonds in the obtained co-network. The oligomer was a joint component of the thiol-ene system along with a tetraallyl-functionalized ditertiary amine curing agent and a radical photoinitiator. The thiol groups of the oligomer reacted with the double bonds of the curing agent to form polythioethers, while the tertiary amine groups of the curing agent induced the anionic ring opening polymerization of the oxirane groups of an epoxy resin to produce polyethers. The kinetics of photopolymerization of the epoxy resin diglycidylet...