Preparation and Characterization of the Lower Equilibrated Phenylsilsesquioxanes

Brown, John F.; Vogt, Lester H.; Prescott, Paul I.

doi:10.1021/ja01060a033

Cited by 277 publications

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“…In our experiment, (4-substituted phenyl)trimethoxysilane was used as the precursor for hydrolysis and condensation instead of phenyltrichlorosilane used by Brown et al 13 in the presence of BTMAOH to avoid the effects of acid liberated which tended to give high molecular weight products, probably because of increasing the rate of condensation reaction of silanol groups. Different from trichlorosilane as the precursor, trimethoxysilane hydrolysis reaction proceeded under easily controllable mild conditions.…”

Section: Resultsmentioning

confidence: 99%

“…1,[3][4][5][6][7] Most of the interests have been focused on hydrido, vinyl and epoxy functional polysilsesquioxane, and the products have been used in high porous materials, 8 nano-composite materials, 9 and catalyst for polymerization, 10 although many unidentified products still exist in the system. During the reaction, both ''intermolecular'' to give randomly branched polymers and ladder polymers, 11 and ''intramolecular'' to give loop structure which eventually forms cyclic polyhedral cage products occur 4,5,12,13 ( Figure 1). The products usually contain unreacted silanol groups depending on their structures.…”

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Tendency of Loop Formation of Oligosilsesquioxanes Obtained from (4-Substituted phenyl)trimethoxysilane Catalyzed by Benzyltrimethylammonium Hydroxide in Benzene

Pakjamsai

Kawakami

2004

Polym J

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ABSTRACT:Products in hydrolysis of (4-substituted phenyl)trimethoxysilane in the presence of benzyltrimethylammonium hydroxide in benzene was studied by matrix-assisted laser desorption/ionization-time of flight mass spectroscopy. In the benzene soluble fraction of 4 h reaction, oligosilsesquioxanes containing 6 to 9 silicon atoms with or without loops were observed. (4-Dimethylaminophenyl)trimethoxysilane gave the fraction containing 6 silicon atoms the least (3%), and 9 silicon fraction the most (36%). Oligosilsesquioxanes containing 9 silicon atoms were formed the least among the products for [4-methoxy-(10%), 4-methyl-(22%), non-(3%), and 4-phenyl-(13%) substituted phenyl]trimethoxysilanes. Oligosilsesquioxanes containing 6 to 8 silicon atoms were the major components of the product irrespective of the substituent. Maximum degree of condensation ( f ) was 0.8 for S 8 , and fully condensed structure was not found. The maximum f ¼ 1:00, and completely closed loop was found in S 9 with one OH group remaining.

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

Tendency of Loop Formation of Oligosilsesquioxanes Obtained from (4-Substituted phenyl)trimethoxysilane Catalyzed by Benzyltrimethylammonium Hydroxide in Benzene

Pakjamsai

Kawakami

2004

Polym J

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“…The reaction mixture was allowed to stand at 25ºC for 4 days and was further refluxed for 24hours. A white, solid powder weighing 79 g (yield 97.8%) was obtained by filtration, and the product (octaphenyl silsesquioxane) was recrystallized using 1,2-dichlorobenzene [16].…”

Section: Synthesis Of Octaphenyl Silsesquioxane (Ops)mentioning

confidence: 99%

Synthesis and Characterization of a POSS-Maleimide Precursor for Hybrid Nanocomposites

Jothibasu

Premkumar

Alagar

et al. 2007

High Performance Polymers

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Epoxy-POSS based hybrid nanocomposites are prepared by in situ polymerization of a homogeneous blend of the diglycidylether of bisphenol-A (DGEBA) and 4,4'-diaminodiphenylmethane (DDM) in the presence of octa(maleimidophenyl)silsesquioxane (OMPS). The reaction of a maleimido-functionalised POSS cube with the epoxy resin is studied by Fourier transform infrared (FTIR) analysis and the formation of nanocomposites is confirmed by wide-angle X-ray diffraction (WAXD) and scanning electron microscopy (SEM). Dynamic mechanical analysis (DMA) studies indicate that the crosslinking structures of the nanocomposite networks are predominantly formed 2 between the terminal maleimide double bonds and the amino groups of DDM through a Michael addition reaction to form an aspartimide. The values of the glass transition temperatures (T g ) decrease with increasing POSS-maleimide content and this is likely to be due to the inclusion of POSS cages into the system and consequent increase in free volume. The dynamic thermal stability of the cured polymers is increased by increasing the POSS content in the hybrid epoxy matrices as evidenced from thermogravimetric analysis (TGA) data.

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“…The fracture surfaces were coated with a thin platinum film in an auto fine coater (JEE-420T, JEOL, Japan). evidence multi siloxane linkages (Si≡(O) 3 ≡Si) of water-crosslinked EPR-g-VTMS [37] and/or a cissyndiotactic ladder configuration of poly(n-hexyl silsesquioxane) (see Scheme 2) [38][39][40]. The spectral difference between PhSO 3 H and PhNH 2 catalyst is consistent with our previous reports on the silane watercrosslinking reaction of EPR-g-VTMS in the presence of various sulfonic acid and amine compounds [41], which is understandable on the traditional knowledge of acid-and base-catalyzed silica sol-gel reaction [7].…”

Section: /28mentioning

confidence: 99%

Ethylene–propylene copolymer/ordered polysilsesquioxane nanocomposites prepared via organic acid‐ or base‐catalyzed binary silica water‐crosslinking reactions

Adachi

Hirano²,

Kasai³

et al. 2009

Polymer International

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BACKGROUND:In-situ silica sol-gel derived organic-inorganic hybrid materials, which comprise a vinyltrimethoxysilane-grafted ethylene-propylene copolymer (EPR-g-VTMS) and n-hexyltrimethoxysilane (HTMS), were successfully prepared in the presence of an organic acid and base catalyst. Benzenesulfonic acid (PhSO 3 H) and aniline (PhNH 2 ) were selected as the organic acid and base catalyst, respectively, to examine the progress and effect of progressive changes in the silane water-crosslinking reaction of EPR-g-VTMS/HTMS composites. RESULTS:The water-crosslinked EPR-g-VTMS/HTMS composites were characterized by means of attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), solid-state silicon-29 cross polarization/magic angle spinning-nuclear magnetic resonance ( 29 Si CP/MAS NMR), wide-angle X-ray scattering (WAXS), tensile strength, and field emission-scanning electron microscope (FE-SEM) measurements. CONCLUSION:These results revealed that the type of catalyst has a substantial influence on the nature of siloxane bands and eventually the physical tensile properties of the water-crosslinked EPR-g-VTMS/HTMS composites, which can be explained mainly on the knowledge of the traditional acid-and base-catalyzed silica sol-gel reaction. Moreover, the in-depth analysis for the PhNH 2 -catalyzed composites indicated the formation of ladder-type poly(n-hexyl silsesquoxane)s and the presence of the highly-ordered structure with a thickness equal to the length of two n-hexyl groups in all-trans conformation. In the present study, we demonstrated a potential for future design of highly-ordered silicate-based organic-inorganic hybrid nanocomposites.3/28

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Preparation and Characterization of the Lower Equilibrated Phenylsilsesquioxanes

Cited by 277 publications

References 0 publications

Tendency of Loop Formation of Oligosilsesquioxanes Obtained from (4-Substituted phenyl)trimethoxysilane Catalyzed by Benzyltrimethylammonium Hydroxide in Benzene

Tendency of Loop Formation of Oligosilsesquioxanes Obtained from (4-Substituted phenyl)trimethoxysilane Catalyzed by Benzyltrimethylammonium Hydroxide in Benzene

Synthesis and Characterization of a POSS-Maleimide Precursor for Hybrid Nanocomposites

Ethylene–propylene copolymer/ordered polysilsesquioxane nanocomposites prepared via organic acid‐ or base‐catalyzed binary silica water‐crosslinking reactions

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