Study on Thiol-vinyl Silizane Cured by UV and Its Pyrolysis Behaviors

摘要

The liquid, containing reactive vinyl-groups ceramic precursor monomer VL20 can be copolymerized with multifunctional thiol monomers by addition of thiol functional group to vinyl silazane functional group with a step-growth polymerization. The copolymer structures are transformed into ceramic structures of a self-similar shape by subsequent pyrolyzing. It provides a convenient way to fabricate ceramic film with heat-defence of aerospace. In this paper, the UV-curing and pyrolysis behaviors of copolymer materials made from different functionality of thiol monomers and VL20 were investigated by using UV-DSC and TGA methods. The results indicated that the maximum polymerization rate was promoted and the final double bond conversion was depressed with increasing the functional degrees of thiol group. DMA results of the UV cured thiol-ene copolymer showed that the Tgof copolymer was increased with increasing of the functionality of thiol group. The TGA results of the cured copolymers showed that the maximum rate of mass loss was enhanced with decreasing of the functionality of thiol group, due to the fact that the ceramic yield was determined by the composition of thiol-ene and was no relevant to the functionality of thiol group. A majority of Si3N4 microcrystalline was obtained after pyrolyzing at 1400 °C for 15 h.