Synthesis and thermal stability properties of boron‐doped silicone resin

ABSTRACT In this article, a novel boron‐doped silicone resin (BSR) was synthesized by hydrolysis‐polycondensation method, with propyl‐triethoxysilane (PTES), dimethyl‐diethoxysilane (DMDES), and boric acid (BA) as starting materials, using absolute ethyl alcohol as solvent and hydrochloric acid as catalyst. The structures of the BSR were characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), X ‐ ray photoelectron spectroscopy (XPS), and gel permeation chromatography (GPC). FTIR spectra showed characteristic BOSi and SiOSi stretching modes. XPS and NMR results confirmed further that boron element was doped successfully into the main chains of the silicone resin as SiOB bond motifs, and hydroxyl groups from BA were condensed properly with SiOH or SiOR to form cross‐linked structure of BSR with narrowed molecular weight distributions in optimum experimental condition. The thermal stability of the BSR was studied by thermogravimetry analysis and derivative thermogravimetry. The thermal degradation temperature of the silicone resin improved greatly after doping element boron into the main chain, and the thermal stability of the BSR was influenced by the content of boron. The thermal degradation mechanism of this BSR was also discussed. The degradation process can be divided into two stages, the weight loss in the first stages may be corresponding to the loss of the small groups and weaker bonds in the chains, such as CH 3 , and C 3 H 7 , the weight loss in the second stage may be corresponding to the loss of the group as OC 2 H 5 . © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 40934.