Synthesis and characterization of a propargyl‐substituted polycarbosilane with high ceramic yield

• Published in: Journal of applied polymer science Vol. 121; no. 6; pp. 3400 - 3406
• Main Authors: Yu, Zhaoju, Li, Ran, Zhan, Junying, Zhou, Cong, Yang, Le, He, Guomei, Xia, Haiping
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 15.09.2011; Wiley; Wiley Subscription Services, Inc
• Subjects: Applied sciences; Ceramics; crystallization; Exact sciences and technology; Heat treatment; hyperbranched; Inorganic and organomineral polymers; Materials science; Physicochemistry of polymers; Polycarbosilanes; polymer synthesis and characterization; Polymers; Preparation; pyrolysis; Reduction; Spectroscopy; Synthesis; Thermal properties; Thermogravimetric analysis; Silane copolymer; Heat treatment; hyperbranched; Acetylenic compound; Branched polymer; Molecular structure; Condensation polymerization; Branched copolymer; Experimental study; Precursor; Thermal stability; Non oxide ceramics; Thermal properties; Silicon carbide; pyrolysis; Preparation; crystallization; Methylene copolymer; polymer synthesis and characterization
• ISSN: 0021-8995; 1097-4628; 1097-4628
• DOI: 10.1002/app.33838

A propargyl‐substituted polycarbosilane (PCS), namely, propargyl‐substituted hyperbranched hydrodipolycarbosilane (PHPCS), was prepared by a modified synthesis route, which involved Grignard coupling of partially methoxylated Cl3SiCH2Cl and CHCCH2Cl, followed by reduction with lithium aluminum hydride. The resultant PHPCSs were characterized by gel permeation chromatography, Fourier transform infrared (FTIR) spectroscopy, and NMR. Moreover, the thermal properties of the PHPCSs were investigated by thermogravimetric analysis. The ceramic yield of PHPCS at 1400°C was about 82.5%, which was about 10 wt % higher than that of hyperbranched hydrodipolycarbosilane without the substitution of propargyl groups. The PHPCS‐derived ceramics were characterized by X‐ray diffraction (XRD), FTIR spectroscopy, and elemental analysis. The XRD and FTIR results indicate that the heat treatment significantly influenced the evolution of crystalline β‐SiC. It can be convenient to get near‐stoichiometric ceramics from PHPCS through the control of feed ratios of the starting materials. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121:3400–3406, 2011