A silicon-containing polymer (HMSA), synthesized with n-BuLi, trichloroethylene, dichloromethylsilane, and dimethyldichlorosilane, with three different proportions of Si–H, and its influence on thermal oxidation have been studied. The structures of HMSA were characterized by Fourier transform infrared spectra, 1H-Nuclear Magnetic Resonance (H-NMR), 13C-NMR, 29Si-NMR, and gel permeation chromatography. Thermal and oxidative stabilities were studied by differential scanning calorimetry and thermogravimetric analysis, and the cross-linking reaction mechanisms of the HMSA were discussed. All the polymers exhibited excellent thermal and oxidation resistance; particularly, HMSA-1 showed high heat-resistant and thermo-oxidative stability; the temperatures of 5% weight loss ( Td5) were 636.3 and 645.5°C, and the residues at 1000°C were 87.07 and 86.23% in nitrogen and air, respectively. This system had excellent thermal and oxidative stability, and through the structure design, control of heat oxidation resistance was realized.
The precursor of poly(carborane)(silicon-acetylene) (PCBS) for silicon carbide (SiC)/B4C composite ceramics was synthesized by a salt metathesis reaction. The molecular weight of PCBS was measured by gel permeation chromatography and the corresponding structures were identified by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR). After thermal curing, the PCBS was converted to a dark red brittle nonporous monolith and the thermal stability was significantly improved, especially in an air atmosphere. Thermogravimetric analysis indicated that the 5% weight loss temperatures were 595°C and 633°C under nitrogen and air atmospheres, respectively, and the corresponding residues at 1000°C were 86.42% and 90.42%. After a heat treatment at 1600°C under inert atmosphere, the well-dispersed SiC/B4C ceramic was obtained and characterized by FTIR, X-ray diffraction analysis, Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The obtained SiC/B4C ceramic has a good high-temperature and oxidation resistance which can be applied to aviation, aerospace, and other ultra-high temperature conditions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.