A new SiC precursor with high ceramic yield: Synthesis and characterization of CH_xMeSiH₂‐containing poly(methylsilane‐carbosilane)

Abstract

A new poly(methylsilane-carbosilane) (PMSCS) for silicon carbide precursor was prepared using Wurtz-type copolymerization of methyldichlorosilane (MeHSiCl 2 ), chloromethyldichloromethylsilane (ClCH 2 MeSiCl 2 ), and (dichloromethyl)methylsilane (Cl 2 CHMeSiH 2 ), with (chloromethyl)methylsilane (ClCH 2 MeSiH 2 ) or trimethylchlorosilane (Me 3 SiCl) as terminated reagent. The ceramic yield of PMSCS was markedly increased by introduction of Cl 2 CHMeSiH 2 comonomer and capped with ClCH 2 MeSiH 2 . The H 2 MeSiCH 2 -capped PMSCS with CHMeSiH 2 structure unit in main chain produced SiC ceramic with 1.21 of C/Si atomic ratio in a ceramic yield of 78 wt % upon pyrolyzed at 1000 C. The excellent pyrolytic properties, combining with its economical preparation, good storage stability in air, and favorable processabilty, make the CH x MeSiH 2 -containing PMSCS a new cost-effective SiC ceramic precursor.

Grignard coupling-based synthesis of vinyl-substituted hydridopolycarbosilane: effect of starting material and polymerization behavior

“…33 Sawai et al and Whitmarsh et al assigned the peak at $2 ppm to -CH 2units in the scaffold and SiCH 2 Cl units, respectively. 34,35 Herein, based on the 1 H NMR spectra of (CH 3 ) 3 -SiCH 2 Cl and (CH 3 )SiOCH 2 CH 3 , 36,37 we conrmed that the peaks observed at 1.5-4 ppm originate from Si-O-alkyl and -SiCH 2 Cl units (Fig. 4).…”

Influence of polycarbosilane composition on the properties of SiC/SiC composite fabricated by precursor infiltration and pyrolysis process

“…Commonly used types include solid polycarbosilanes (PCSs), perhydrogen PCSs (HPCSs), polymethylsilane (PMS), etc. 18,[21][22][23] Among others, PCS remains the most commercialized SiC ceramic precursor. However, the ceramic products derived from PCS contain more free carbon.…”

“…In recent decades, extensive research has been conducted to prepare SiC ceramic polymer precursors. Commonly used types include solid polycarbosilanes (PCSs), perhydrogen PCSs (HPCSs), polymethylsilane (PMS), etc 18,21–23 . Among others, PCS remains the most commercialized SiC ceramic precursor.…”

C/C–SiC composites derived from single‐source poly(silylene–acetylene) precursors

“…However, the high melting point of PCS makes it difficult to prepare C/C–SiC ceramic composites. Various functional groups were introduced into the main chain of PCS in an attempt to solve processing difficulties, but this effort did not produce the desired outcome 18 …”

“…Various functional groups were introduced into the main chain of PCS in an attempt to solve processing difficulties, but this effort did not produce the desired outcome. 18 Advanced PCPs have also attracted the attention of researchers. Chemistry plays a major role in the precise control of the chemical compositions and microstructure of ceramics at low processing temperatures using welldefined single-source precursors.…”