Grignard condensation routes to 1,3‐disilacyclobutane‐containing cyclolinear polycarbosilanes

Abstract

Alkylene‐ and arylene‐bridged cyclolinear polycarbosilanes (CLPCS) with 1,3‐disilacyclobutane (DSCB) rings incorporated in the main chain of the polymer were prepared by polycondensation between corresponding di‐functional DSCB derivatives and di‐Grignard reagents. Well‐defined, low molecular weight (Mn = 3–5K; DP = 17–26), hexylene‐ and phenylene‐bridged CLPCS polymers were obtained without appreciable ring opening of the DSCB rings. Large exothermic peaks were observed in the DSC for these CLPCSs, which indicated, along with the IR spectra, that crosslinking occurred on heating to about 250 °C via the ring opening of the embedded, alternating, DSCB rings. Moreover, PB‐CLPCS undergoes photochemically induced crosslinking on UV irradiation to form crosslinked polycarbosilane network films. The spin‐cast, cured, films of these CLPCSs exhibit relatively low dielectric constants and promising thermal and mechanical properties for applications in electronics, for example, directly UV‐photoimprinted low‐k dielectrics. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 1547–1557

UV-Cured Transparent Flexible Silicone Materials with High Tensile Strength

“…20,21 The cross-linkable carbosilane polymers exhibit intriguing physical and chemical properties, which could be used as anticorrosion coatings. 22,23 A silicon-containing hyperbranched polycarbosilane, particularly phosphorus-hyperbranched carbosilanes, and a sulfur-containing hyperbranched polycarbosilane have emerged promising applications in polymer-derived ceramics, room-temperature-vulcanized silicone rubber, hightemperature-vulcanized silicone rubber, and coatings. 20,24,25 Inspired by these efforts, the silicon-containing hyperbranched polycarbosilane may be used to improve the corrosion resistance of the materials.…”

Hyperbranched Polycarbosiloxanes: Synthesis by Piers-Rubinsztajn Reaction and Application as Precursors to Magnetoceramics

“…Among these HBPs, silicon-containing HBPs (Si-HBPs) are one of most important species and have attracted specific interest due to their potentials as silicon carbide ceramic precursors, degradable template molecules, optical materials, modifiers of composites, cell imaging, drug delivery, and gas chromatography [8][9][10][11][12][13][14][15]. The Si-HBPs can be prepared by several strategies, including hydrosilylation reactions from silicon-containing monomers containing Si-H bonds and unsaturated bonds (e.g., vinyl or alkynyl) [16,17], organometallic reaction (e.g., Grignard reaction) [13,18] and polycondensation reaction [19]. However, these strategies have some disadvantages.…”

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

“…The Grignard coupling-based synthesis of polycarbosilanes has already been investigated in terms of mechanism, structural characteristics, kinetics, and side reactions; [8][9][10][11] however, out current understanding of polycarbosilane growth via this method is very limited. 12,13 For example, Guodong and Jang analyzed and discussed the change in the properties of polycarbosilane with the growth behavior of the polymer, but it is limited to the Yajima method. 14,15 In other cases, molecular weight was analyzed only to evaluate individual synthesis conditions, and the studies related to polymer growth were very insignicant.…”

“…14,15 In other cases, molecular weight was analyzed only to evaluate individual synthesis conditions, and the studies related to polymer growth were very insignicant. [16][17][18]27 Therefore, in order to prepare the suitable precursor for the required properties of each different eld, it is necessary to understand growth behavior of the polymer and to control the reaction condition accordingly.…”