Liquid polycarbosilanes: synthesis and evaluation as precursors for SiC ceramic

A series of liquid polycarbosilanes were successfully synthesized by a sequential Grignard coupling reaction of (chloromethyl)triethoxysilane and vinylmagnesium bromide, followed by reduction with lithium aluminium hydride. The use of non-corrosive, easily handleable and storage stable (chloromethyl)triethoxysilane as starting material is an attractive advantage for this route. The as-synthesized polymers containing Si-CH=CH2 and Si - H groups are storage stable and can be easily cured in an inert atmosphere. The ceramic yield of the cured polycarbosilane and the C:Si ratio of the derived ceramic were varied by adjusting the mole ratio of starting materials in the feed. Among them, the polymer with a mole ratio of Si-CH=CH2 to Si - H of 1:10 has the highest ceramic yield at 89.6% after curing at 220 degrees C and the C:Si ratio of the derived ceramic is 1.48. This kind of polycarbosilane shows high potential as an SiC ceramic precursor in the fabrication of an SiC matrix by the precursor infiltration pyrolysis process. (c) 2015 Society of Chemical Industry

[1]  Litong Zhang,et al.  One-pot synthesis and characterization of a new, branched polycarbosilane bearing allyl groups , 2007 .

[2]  R. Nemanich,et al.  First- and second-order Raman scattering from finite-size crystals of graphite , 1979 .

[3]  R. Raj,et al.  Amorphous Silicoboron Carbonitride Ceramic with Very High Viscosity at Temperatures above 1500°C , 1998 .

[4]  L. Interrante,et al.  Modification of a Hyperbranched Hydridopolycarbosilane as a Route to New Polycarbosilanes , 1997 .

[5]  L. Interrante,et al.  Mechanical, thermochemical and microstructural characterization of AHPCS-derived SiC , 2012 .

[6]  J. Robertson,et al.  Interpretation of Raman spectra of disordered and amorphous carbon , 2000 .

[7]  M. Akinc,et al.  Green State Joining of SiC without Applied Pressure , 2001 .

[8]  Xiao‐nong Cheng,et al.  Synthesis of hierarchical porous silicon oxycarbide ceramics from preceramic polymer and wood biomass composites , 2014 .

[9]  L. Interrante,et al.  Hyperbranched Polycarbosilanes via Nucleophilic Substitution Reactions , 2009 .

[10]  G. Ziegler,et al.  Characterization of the Free‐Carbon Phase in Precursor‐Derived Si‐C‐N Ceramics: I, Spectroscopic Methods , 2004 .

[11]  J. Moreau,et al.  Polyfunctional carbosilanes and organosilicon compounds. Synthesis via grignard reactions , 1993 .

[12]  Lai-fei Cheng,et al.  Effect of the polycarbosilane structure on its final ceramic yield , 2008 .

[13]  F. Aldinger,et al.  A silicoboron carbonitride ceramic stable to 2,000°C , 1996, Nature.

[14]  H. Kleebe,et al.  Newtonian Viscosity of Amorphous Silicon Carbonitride at High Temperature , 2005 .

[15]  R. Riedel,et al.  Single-source-precursor synthesis of high temperature stable SiC/C/Fe nanocomposites from a processable hyperbranched polyferrocenylcarbosilane with high ceramic yield , 2014 .

[16]  R. Laine,et al.  Processing stoichiometric silicon carbide fibers from polymethylsilane. Part 1 Precursor fiber processing , 1998 .

[17]  S. Yajima,et al.  Synthesis of continuous silicon carbide fibre with high tensile strength and high Young's modulus , 1978 .

[18]  Sung-tag Oh,et al.  Low-temperature chemical vapour curing using iodine for fabrication of continuous silicon carbide fibres from low-molecular-weight polycarbosilane , 2014 .

[19]  Litong Zhang,et al.  Synthesis, Characterization, and Pyrolytic Conversion of a Novel Liquid Polycarbosilane , 2008 .

[20]  M. Kumada,et al.  Evidence for “silylenoid” species in disproportionation of pentamethyldisilane catalyzed by trans-[PtCl2 (Et3P)2] , 1971 .

[21]  Yoshio Hasegawa,et al.  Synthesis of continuous silicon carbide fibre with high tensile strength and high Young's modulus , 1978 .

[22]  M. Edirisinghe,et al.  Effect of pre-pyrolysis heat treatment on the preparation of silicon carbide from a polycarbosilane precursor , 1999 .

[23]  L. Sneddon,et al.  Silicon-based ceramics from polymer precursors , 2002 .

[24]  K. W. Chew,et al.  α-Silicon carbide/β-silicon carbide particulate composites via polymer infiltration and pyrolysis (PIP) processing using polymethylsilane , 2000 .

[25]  Mamoru Omori,et al.  Synthesis of Continuous Sic Fibers with High Tensile Strength , 1976 .

[26]  M. Bradley,et al.  Synthesis and Ceramic Conversion Reactions of 9-BBN-Modified Allylhydridopolycarbosilane: A New Single-Source Precursor to Boron-Modified Silicon Carbide , 2003 .

[27]  政規 小谷,et al.  アリルハイドライドポリカルボシラン(AHPCS)を用いたSiC/SiC複合材料の作製とその耐酸化特性 , 2003 .

[28]  M. Omori,et al.  CONTINUOUS SILICON CARBIDE FIBER OF HIGH TENSILE STRENGTH , 1975 .

[29]  R. Riedel,et al.  Carbon-rich SiCN ceramics derived from phenyl-containing poly(silylcarbodiimides) , 2009 .

[30]  L. Interrante,et al.  Synthesis and structure of a highly branched polycarbosilane derived from (chloromethyl)trichlorosilane , 1991 .

[31]  F. Tuinstra,et al.  Raman Spectrum of Graphite , 1970 .

[32]  F. Huang,et al.  A Novel Oxidation Resistant SiC/B4C/C Nanocomposite Derived from a Carborane‐Containing Conjugated Polycarbosilane , 2012 .

[33]  H. Xia,et al.  Preparation, cross-linking and ceramization of AHPCS/Cp2ZrCl2 hybrid precursors for SiC/ZrC/C composites , 2012 .