69655-76-1Relevant articles and documents
Crosslinking of low density polyethylene with octavinyl polyhedral oligomeric silsesquioxane as the crosslinker
Wu, Jiachun,Wu, Zi Liang,Yang, Hongmei,Zheng, Qiang
, p. 44030 - 44038 (2014)
We report a new strategy for the crosslinking of low density polyethylene (LDPE) by using a small amount of functional nanostructured hybrid agent, octavinyl polyhedral oligomeric silsesquioxane (OVPOSS), as the crosslinker, which dramatically decreases the amount of dicumyl peroxide (DCP) and thus avoids the chain scission, scorch, and production of small pores in the conventional peroxide crosslinking strategy. By melt blending under an extruder, OVPOSS aggregates with sizes of tens of nanometers are homogeneously distributed in the matrix of LDPE, as confirmed by SEM. FTIR, DSC, and rheometry are used to study the crosslinking process and product properties. We found that vinyl groups of OVPOSS are firstly activated by the initiator of DCP and then react with LDPE to form an integrated network. The crosslinking process is fast and highly efficient because each OVPOSS molecule has eight reactive vinyl groups. The reactions complete within 10 min at 175 °C, and speed up with the increase in the content of DCP or OVPOSS. In the presence of 0.2 phr DCP, 0.5 wt% OVPOSS can effectively crosslink the composite sample with comparable properties to that with 2 phr DCP yet without OVPOSS. The obtained crosslinked LDPE should be suitable for high voltage cable materials. We believe that the approach using functional agents is powerful to crosslink or functionalize other polymers for special properties and applications.
Hexa(organylsilsesquioxanes)
Basenko,Maylyan
, p. 1034 - 1038 (2016)
A method for the synthesis of earlier practically unknown hexa(organylsilsesquioxanes) (RSiO1,5)6 have been developed based on the reaction of organyltrichlorosilanes RSiCl3 (R = Et, Vin) with DMSO. The reaction proceeded in several steps. The initial stage of the reaction gave poorly available 1,3,5-trichloro-1,3,5-triorganylcyclosiloxanes in 40—80% yield, as well as organyl(chloro)oligohomosilsesquioxanes, which further are converted to the corresponding organyloligosilsesquioxanes. Based on the monitoring of the reaction mixture by GC-MS, a scheme for the formation of the intermediate silsesquioxane structures have been suggested.
Construction of bimodal silsesquioxane-based porous materials from triphenylphosphine or triphenylphosphine oxide and their size-selective absorption for dye molecules
Shen, Rong,Liu, Hongzhi
, p. 37731 - 37739 (2016)
Two novel hybrid porous polymers were easily prepared by the Friedel-Crafts reaction of octavinylsilsesquioxane with triphenylphosphine and triphenylphosphine oxide, respectively. They possessed unique bimodal pores with uniform micropores and mesopores centered at 1.5 nm and 3.7 nm, respectively, high surface areas up to 1105 m2 g-1, high thermal stability and an excellent size-selective adsorption for dyes. These hybrid porous polymers are very promising in dye separation, water purification and treatment.
Studies of octameric vinylsilasesquioxane by carbon-13 and siIicon-29 cross polarization magic angle spinning and inversion recovery cross polarization nuclear magnetic resonance spectroscopy
Bonhomme, Christian
, p. 1617 - 1626 (1997)
The acidic hydrolysis of triethoxyvinylsilane Si(C2H3)(OEt)3 led to octavinyloctasilasesquioxane (C2H3SiO,j)81 . and to a transparent derived gel 2. Compound 1 was obtained as single crystals, suitable for X-ray analysis: trigonal, space group β3, Z = 3, a = 13.533(2), c = 14.222(2) A, y = 120°. Disorder of the methylene groups was observed. Compound 1 was carefully studied by IR spectroscopy and 29Si/13C cross polarization magic angle spinning (CP MAS) NMR spectroscopy. The CP dynamics of the various I3C sites were analysed by inversion recovery cross polarization (IRCP). Very different behaviours were observed for CH and CH2 signals and could be attributed to anisotropic reorientations of the vinyl groups. The IRCP sequence enabled a complete editing of the spectra and definite assignments of the observed lines. Owing to its highly resolved spectra and small intrinsic linewidths, it appears that compound 1 could act as a secondary reference for the set-up of the Hartmann-Hahn condition in 29Si CP NMR spectroscopy as well as a test for the set-up of the magic angle. All these results were applied to the study of the amorphous gel 2. Dipolar coupling constants were also strongly affected by local motions. .
Monolithic nanoporous polymers bearing POSS moiety as efficient flame retardant and thermal insulation materials
Wang, Fei,Wei, Huijuan,Liu, Chao,Sun, Hanxue,Zhu, Zhaoqi,Liang, Weidong,Li, An
, (2019)
The creation of porous materials with both good thermal insulation and flame retardancy is of great importance for construction of energy-saving coatings in many applications. Herein, we report the facile fabrication of octasilsesquioxane (POSS)-based monolithic nanoporous polymers (named as PDVB-POSS) by solvothermal method using octavinyl-POSS as monomer and divinylbenzene (DVB) as crosslinker followed by freeze drying. The as-prepared PDVB-POSS show abundant porosity with mesopore sizes ranging from 8 nm to 13 nm, which results in a high thermal insulation with a low thermal conductivity of 0.024 W m?1 k?1 in air. The PDVB-POSS also possesses excellent flame retardancy with a peak heat released rate (pHRR) of as low as 144 W g?1. Torch burn test implies that the PDVB-POSS shows self-extinguishing behaviors without generation of any melt dripping, further reflecting an excellent flame retardancy. Taking advantages of simple fabrication process, easily to be scaled-up, excellent thermal insulation and flame retardancy, such POSS-based monolithic porous polymers may have great potential as energy-saving coatings for real applications.
Highly efficient latent fingerprint detection by eight-dansyl-functionalized octasilsesquioxane nanohybrids
Díaz Díaz, David,Dare, Enock O.,Jiménez, M. Consuelo,Pérez-Ruiz, Raúl,Vendrell-Criado, Victoria
, (2020/09/17)
The largely demand in continued security issues makes necessary the development of novel materials with outstanding properties to improve the current detection techniques. In this context, latent fingerprint (LF) by fluorescent labeled materials (FLM) is one of the most attractive personnel identification methodologies. Here, two FLM based on polyhedral oligomeric silsesquioxane (POSS) nanohybrids labeled with dansyl chromophores have been synthesized and fully characterized. Their photophysical properties have confirmed that these materials clearly possess the prime qualifications as suitable LF sensing platforms. In fact, they adequately detect LFs on glassy surface with excellence legibility.
TREATED SUBSTRATE HAVING HYDROPHOBIC AND DURABILITY PROPERTIES
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Paragraph 00105; 00106, (2019/03/12)
A treated substrate comprise a substrate, an adhesion promoter layer disposed on the substrate, and a topcoat layer disposed on the adhesion layer such that the adhesion layer is between the topcoat layer and the substrate. The adhesion promoter layer is formed from an adhesion promoter composition, with the adhesion promoter composition comprising a polyhedral oligomeric silsesquioxane or a linear organosilane polymer. The topcoat layer is formed from a topcoat composition, with the topcoat composition comprising at least one fluorinated organic silicon compound which contains no etheric oxygen atom and at least one fluorinated organic silicon compound which contains an etheric oxygen atom.
POSS-derived solid acid catalysts with excellent hydrophobicity for highly efficient transformations of glycerol
Leng, Yan,Zhao, Jiwei,Jiang, Pingping,Lu, Dan
, p. 875 - 881 (2016/02/18)
Novel excellent hydrophobic POSS-derived solid acid catalysts were successfully synthesized through free radical copolymerization of polyhedral oligomeric vinylsilsesquioxanes (POSS) with sodium p-styrene sulfonate (POSS-x-SO3H), and characterized by several physicochemical methods. Green routes toward valorization of glycerol via acetalization with benzaldehyde and esterification of glycerol with acetic acid have been proposed. The as-prepared catalysts showed very high activities and selectivities toward glycerol derivatives within a short reaction time, which were even higher than that of homogeneous H2SO4. The POSS-2-SO3H catalyst was recycled up to five times without any significant loss of activity. The excellent performance of these solid acid catalysts is mostly attributed to the combination of superior hydrophobicity and large specific surface area.
POSS-derived mesoporous ionic copolymer-polyoxometalate catalysts with a surfactant function for epoxidation reactions
Zhao, Jiwei,Leng, Yan,Jiang, Pingping,Wang, Jun,Zhang, Chenjun
, p. 1022 - 1028 (2016/02/19)
A series of novel polyoxometalate (POM)-based stable polymeric hybrids were successfully synthesized using polyhedral oligomeric vinylsilsesquioxanes (POSS) and ionic liquids (IL) bearing hydrophobic alkyl chains as the building blocks, followed by ion exchange with Keggin-type phosphotungstic acid (PW). The obtained hybrids POSS-ILx-PW were demonstrated to be mesostructured and amphiphilic materials with good thermal stability. Catalytic tests for the H2O2-based epoxidation of cyclooctene have shown that these newly designed catalysts exhibit extraordinary catalytic activities, catalytic rates, and quite stable reusability. The unique amphiphilic property and the mesoporous structure are revealed to be responsible for the catalysts' excellent performance in epoxidation reactions with H2O2.
Theoretical and experimental investigations on mono-substituted and multi-substituted functional polyhedral oligomeric silsesquioxanes
Xia, Yong,Yao, Hongtao,Cui, Meifang,Ma, Yun,Kong, Zhineng,Wu, Baoying,Qi, Zhengjian,Sun, Yueming
, p. 80339 - 80345 (2015/10/05)
The structure and electronic properties of polyhedral oligomeric silsesquioxane (POSS) cages functionalized with mono-substituted and multi-substituted vinyl and mercaptopropyl have been studied using density functional theory calculations. Electron density distributions and frontier molecular orbitals (FMOs) have been constructed at the B3LYP/6-31+G(d) level to understand the electronic properties. 1H, 13C, and 29Si NMR spectra by using the gauge including atomic orbital (GIAO) method of the studied compounds were compared with experimental data obtained.
