Thiol-ene photopolymerization of polymer-derived ceramic precursors

The liquid, ceramic precursor monomer VL20 was copolymerized with a thiol monomer in a traditional radical thiol-ene photopolymerization. Polymerization occurred via addition of the thiol functional group to the vinyl silazane functional group in a 1:1 ratio consistent with a step-growth polymerization. Gelation occurred at a high conversion of functional groups (70%) consistent with an average molecular weight and functionality of 560 and 1.7, respectively, for VL20 monomers. Initiatorless photopolymerization of the thiol-VL20 system also occurred upon irradiation at either 365 or 254 nm. (C) 2004 Wiley Periodicals, Inc.