Thermosetting Mechanism Study of Poly[(phenylsilylene)ethynylene-1,3-phenyleneethynylene] by Solid-State NMR Spectroscopy and Computational Chemistry

Abstract

Poly[(phenylsilylene)ethynylene-1,3-phenyleneethynylene] (abbreviated MSP) which contains Si−H and C⋮C bonds, produces a very highly thermally stable polymer by curing above 150 °C. In this study, we determined the thermosetting mechanism of MSP using 13C and 29Si solid-state NMR methods and computational chemistry. From these results, we concluded that the intermolecular cross-linking reactions due to (1) the Diels−Alder reaction between Ph−C⋮C and C⋮C and (2) the hydrosilylation reaction between Si−H and C⋮C proceed above 150 °C, and a very highly thermally stable structure is formed. Only the hydrosilylation reaction occurs above 300 °C.