Poly(vinylsilane), [CH2CH(SiH3)]n: Preparation, Characterization, and Utilization as a Preceramic Polymer

Abstract

Lithium aluminum hydride reduction of poly(vinyltrichlorosilane), prepared by 60Co y-radiation-induced polymerization of CH2=CHSiCl3, gave poly(vinylsilane), PVSiHs. The composition of this low molecular weight polymer was determined by and 29Si NMR spectroscopy to be C^-CCSiHsXCHzCHCSiHslMC^CHCSiHslCHtSiHslCHzM > CHCH2-SiH2)z-(* > y » z). Pyrolysis of PVSiHs in argon to 1500 °C gave only a moderate (ca. 40%) ceramic residue yield. However, PVSiHs could be cross-linked by the action of various group 4 metallocene derivatives to give soluble polymers whose pyrolysis in argon gave substantially improved yields (70-80%) of ceramic residue composed of silicon carbide together with 10-13 wt % of carbon.

Effect of polyborazine additive on thermolysis of polyphenylsilane and polyvinylsilane

“…PPS was prepared by the dehydropolymerization of PhSiH 3 with Cp 2 TiCl 2 /Red-Al catalyst, followed by flash chromatography (packed with Florisil † ) with toluene as eluent [2]. PVS was prepared by polymerization of CH 2 Ä/CH Ã/Si(OEt) 3 in the presence of t Bu 2 O initiator at 130 8C for 6 h followed by reaction of resulting polymer with LiAlH 4 [3]. PBN was synthesized according to the method described in our previous work [9].…”

“…Integration ratios of Si Ã/ C 6 H 5 /Si Ã/H increased from an initial d 5.0 to d 5.2, as shown in Table 2, indicating that some of the SiÃ/H groups are consumed by the dehydrocoupling reaction. In PVS, peaks at d 0.6 Á/1.8 and d 3.4 Á/3.6 were assigned to SiÃ/CH CH 2 and SiÃ/H , respectively [3]. Integration ratios of Si Ã/CH CH 2 /Si Ã/H increased from an initial d 2.82 to d 3.05.…”

“…Preceramic polycarbosilane (PCS), used for preparing commercial Nicalon fibers, is synthesized by the low efficient thermolysis of polydimethylsilane (PDMS) [1]. As an alternative precursor for SiC ceramics, we studied polyphenylsilane (PPS, [SiH(Ph)] n ) [2] and polyvinylsilane (PVS, [CH 2 CH(SiH 3 )] n ) [3]. An ideal preceramic precursor for SiC ceramics should exhibit (1) high ceramic residue yield, to minimize the cost and volume changes associated with pyrolytic conversion to ceramics and consequently to maximize the control of porosity and densification, and (2) a suitable processability (i.e.…”

Ein Konzept zur Syntheseplanung in der Festkörperchemie

“…[6,10,110,111] Als wichtigste genannt seien Cof‰llung, thermischer Abbau von Vorl‰ufern (z. [120,121] Besonders wirkungsvoll l‰sst sich die erforderliche Aktivierung durch Anwendung von chemischem Transport, [122±125] von Schmelzreaktionen, [126±130] von Solvothermalsynthesen [131] oder von topotaktischen Umsetzungen (Intercalation, Deintercalation) herabsetzen. [120,121] Besonders wirkungsvoll l‰sst sich die erforderliche Aktivierung durch Anwendung von chemischem Transport, [122±125] von Schmelzreaktionen, [126±130] von Solvothermalsynthesen [131] oder von topotaktischen Umsetzungen (Intercalation, Deintercalation) herabsetzen.…”

Polycarbosilane based UD C/SiC composites: Effect of in-situ grown SiC nano-pins on mechanical properties

“…SiC has been considered for many high temperature applications due to its unique mechanical and thermal properties [5,6]. Therefore, a variety of Polycarbosilanes (PCS) have been synthesized so far, to generate SiC fiber/matrix [6][7][8][9].…”