- DEHYDROCONDENSATION OF HYDROGEN-CONTAINING CYCLOSILOXANES
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The dehydrocondensation of hydrogen-containing cyclosiloxanes under alkali conditions has been studied.The reaction was found to have two alternative courses depending on the conditions.A quantative yield of cyclolinear ladder polymers, their catalytic re
- Martynova, T. N.,Korchkov, V. P.
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- Simple and rapid eco-fnendly synthesis of cubic octamethylsilsesquioxane using microwave irradiation
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Octamethylsilsesquioxane (Me8Si8O12) having a cage structure was rapidly prepared by means of microwave-assisted sol-gel reaction of methyltrimethoxysilane as a trifunctional alkoxysilane with an aqueous basic solution in diglyme as a solvent. Moreover, octamethylsilsesquioxane was obtained as cubic particles in a good yield. Cubic octamethylsilsesquioxane could be formed under microwave irradiation owing to the formation of micelles which are organized by eight methyltrimethoxysilane molecules in diglyme.
- Iwamura, Takeru,Adachi, Kaoru,Chujo, Yoshiki
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- Problems of synthesis of tetrahedral organosilsesquioxanes. Hydrolytic condensation of hexafunctional branched organotetrasiloxanes
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The hydrolytic condensation of methyltris(methyldichlorosiloxy)silane (1b), methyl- (1a), and vinyltris(methyldiethoxysiloxy)silanes (1c) in dilute homogeneous solutions was studied.It was found by X-ray diffraction and 1H NMR methods that, irrespective o
- Rebrov, E. A.,Tebeneva, N. A.,Mouzafarov, A. M.,Ovchinnikov, Yu. E.,Struchkov, Yu. T.,Strelkova, T. V.
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- Influences of polyhedral oligomeric silsesquioxanes (POSSs) containing different functional groups on crystallization and melting behaviors of POSS/polydimethylsiloxane rubber composites
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In this article, three kinds of polyhedral oligomeric silsesquioxanes (POSSs) - octamethylsilsesquioxane (OMS), octaphenylsilsesquioxane (OPS) and heptaphenylhydrogensilsesquioxane (H-POSS) - were successfully synthesized. Then, POSSs were incorporated into polydimethylsiloxane (PDMS) rubber through solution blending followed by open two-roll mill blending with curing agent. Finally, the blends were cured with a plate vulcanizing press and the effects of POSSs on crystallization and melting behaviors of PDMS were investigated. DSC tests indicated that crystallinity (Xc) of the OMS/PDMS composite was lowered, while Xcand the melting temperature (Tm) of the OPS/PDMS composite could be significantly enhanced when 20 wt% OPS was incorporated. OPS was proved to play a role as a nucleating agent in the crystallization of PDMS, but its nucleation mechanism was different from H-POSS which was previously studied by us. The crystals of OPS were flake-like with huge surfaces which provide templates for PDMS crystals to grow. However, due to the grafting of H-POSS onto PDMS chains, H-POSS played a role as physical crosslinking points to reduce the mobility of the PDMS chain segments. This journal is
- Zhang, Dian,Shi, Yunhui,Liu, Yufeng,Huang, Guangsu
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- Incompletely condensed POSS-based spin-on-glass networks for impeccable ultra low-k integration
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Poly(methyl)silsesquioxane-based spin-on-glass resins incorporating both a cyclic precursor, 1,3,5,7-tetramethyl 1,3,5,7-tetrahydroxyl cyclosiloxane, and incompletely condensed methyl-substituted POSS were synthesized and their thermal, mechanical, and el
- Lee, Albert S.,Choi, Seung-Sock,Oh, Sung Yeoun,Lee, He Seung,Kim, Bomin,Hwang, Seung Sang,Baek, Kyung-Youl
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- Preparation of polysilsesquioxane (CH3SiO1.5) 8 crystals from swollen PHEMA
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Polysilsesquioxane (CH3SiO1.5)8 crystals were prepared from CH3Si(OCH2CH3) 3-trapped poly(2-hydroxyethylmethacrylate) (PHEMA) swollen in methanol in 23% yield under certain acidi
- Luo, Qun,Tang, Daihua,Li, Xiaodong,Wang, Qi,Wang, Zhipeng,Zhen, Zhen,Liu, Xinhou
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- One-Step Synthesis of Siloxanes from the Direct Process Disilane Residue
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The well-established Müller–Rochow Direct Process for the chloromethylsilane synthesis produces a disilane residue (DPR) consisting of compounds MenSi2Cl6?n(n=1–6) in thousands of tons annually. Technologically, much effort is made to retransfer the disilanes into monosilanes suitable for introduction into the siloxane production chain for increase in economic value. Here, we report on a single step reaction to directly form cyclic, linear, and cage-like siloxanes upon treatment of the DPR with a 5 m HCl in Et2O solution at about 120 °C for 60 h. For simplification of the Si?Si bond cleavage and aiming on product selectivity the grade of methylation at the silicon backbone is increased to n≥4. Moreover, the HCl/Et2O reagent is also suitable to produce siloxanes from the corresponding monosilanes under comparable conditions.
- Neumeyer, Felix,Auner, Norbert
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supporting information
p. 17165 - 17168
(2016/11/23)
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- Influences of polyhedral oligomeric silsesquioxanes (POSSs) containing different functional groups on crystallization and melting behaviors of POSS/polydimethylsiloxane rubber composites
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In this article, three kinds of polyhedral oligomeric silsesquioxanes (POSSs) - octamethylsilsesquioxane (OMS), octaphenylsilsesquioxane (OPS) and heptaphenylhydrogensilsesquioxane (H-POSS) - were successfully synthesized. Then, POSSs were incorporated into polydimethylsiloxane (PDMS) rubber through solution blending followed by open two-roll mill blending with curing agent. Finally, the blends were cured with a plate vulcanizing press and the effects of POSSs on crystallization and melting behaviors of PDMS were investigated. DSC tests indicated that crystallinity (Xc) of the OMS/PDMS composite was lowered, while Xc and the melting temperature (Tm) of the OPS/PDMS composite could be significantly enhanced when 20 wt% OPS was incorporated. OPS was proved to play a role as a nucleating agent in the crystallization of PDMS, but its nucleation mechanism was different from H-POSS which was previously studied by us. The crystals of OPS were flake-like with huge surfaces which provide templates for PDMS crystals to grow. However, due to the grafting of H-POSS onto PDMS chains, H-POSS played a role as physical crosslinking points to reduce the mobility of the PDMS chain segments. This journal is
- Zhang, Dian,Shi, Yunhui,Liu, Yufeng,Huang, Guangsu
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p. 41364 - 41370
(2015/05/20)
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- HETEROSUBSTITUTED METHYL-γ-TRIFLUOROPROPYLOCTASILSESQUIOXANES
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Synthesis of heterosubstituted methyl-γ-trifluoropropyloctasilsesquioxanes with the general formula (CH3)n(CH2CH2CF3)8-n(SiO1.5)8, where n = 1-7, has been performed by co-hydrolysis of corresponding trichlorosilanes in alcohol medium. Volatile products of
- Lavrent'ev, V. I.,Durasov, V. B.
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p. 2248 - 2252
(2007/10/02)
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- Heterofunctional oligoorganylsilsesquioxanes
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The results of studies of the synthesis processes and some physico-chemical properties of heterofunctional octa(methylvinyl)silsesquioxanes of the general formula RnR'8-n8, where n = 0-8, R = CH3, are reported.It has benn sho
- Martynova, T.N.,Chupakhina, T.I.
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