- Flexible conductive polypyrrole nanocomposite membranes based on bacterial cellulose with amphiphobicity
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Flexible conductive polypyrrole nanocomposite membranes based on bacterial cellulose (BC) with amphiphobicity have been successfully prepared through in situ chemical synthesis and then infiltrated with polysiloxane solution. The results suggested that polypyrrole (PPy) nanoparticles deposited on thesurface of BC formed a continuous coreshell structure by taking along the BC template. After modification with polysiloxane, the surface characteristics of the conductive BC membranes changed from highly hydrophilic to hydrophobic. The AFM images revealed that the roughness of samples after polysiloxane treatment increased along with the increase of pyrrole concentration. The contact angles (CAs) datarevealed that the highest water contact angle and highest oil contact angle are 160.3and 136.7, respectively. The conductivity of the amphiphobic membranes with excellent flexibility reached 0.32 S/cm and demonstrated a good electromagnetic shielding effectiveness with an SE of 15 dB which could be applied in electromagnetic shielding materials with self-cleaning properties. It opened a new field of potential applications of BC materials.
- Tang, Lian,Han, Jinlu,Jiang, Zhenlin,Chen, Shiyan,Wang, Huaping
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- Preparation of spherical poly(methylsilsesquioxanes) beads and their properties
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The spherical poly(methylsilsesquioxane) (PMSQ) beads with the diameter of 2, 5 and 10 micron, respectively were prepared from methyltrimethoxysilane (MTMS) by two steps, acid hydrolysis and base condensation process in aqueous solution. Acetic acid and a
- Chae, Heon Seung,Song, Seog Jeong,Park, Yun Heum
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- A simplified fabric phase sorptive extraction method for the determination of amphetamine drugs in water samples using liquid chromatography-mass spectrometry
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Fabric phase sorptive extraction (FPSE) can directly extract the target analytes and simultaneously determine many similar substances from complicated sample matrices. Also, it has very high chemical stability. Therefore, we used fabric phase sorptive extraction to analyze three amphetamine drugs (amphetamine (AM), methamphetamine (MAM), and 3,4-methylenedioxymethamphetamine (MDMA)) in water. This was coupled with ultrahigh-performance liquid chromatography and tandem mass spectrometry. The effects of different sorbent chemistries such as sorption time, ratios of back-extraction solvents, back-extraction time, and the salt effect on the extraction efficiency were studied; the optimum operation conditions were determined. Medium polarity polar polymer-coated FPSE media were created using short-chain poly (tetrahydrofuran) (PTHF). This is the most efficient extraction media for the analytes of interest. Under the optimized conditions, the linear range of the three amphetamine drugs were 0.1-150.0 (AM, MAM) and 0.5-200 ng mL-1 (MDMA). The correlation coefficients (γ) were 0.9947 (AM), 0.9925 (MAM), and 0.9918 (MDMA). The detection limits (LOD) were 0.025 ng mL-1 for AM, 0.029 ng mL-1 for MAM, and 0.01 ng mL-1 for MDMA. The corresponding limit of quantification values (LOQ) were 0.083 ng mL-1, 0.097 ng mL-1, and 0.031 ng mL-1, respectively. The recoveries were 73.4-91.6%, 82.6-95.4%, and 92.7-95.3%, respectively, and the relative standard deviations (RSD) were 1.65-6.88%, 1.38-6.11%, and 1.58-7.34%, respectively. Moreover, our method can be successfully applied for the analysis of amphetamines in wastewater samples, and at the same time, lays the foundation for the future detection of such substances.
- Li, Shiying,Peng, Ju,Ruan, Xiaomeng,Song, Yiqun,Sun, Qianqian,Xing, Limei
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- Silanol Compound, Composition, and Method for Producing Silanol Compound
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The purpose of the present invention is to provide silanol compounds that can be used as raw materials of siloxane compounds and the like, and a composition of the silanol compounds, as well as to provide a production method that makes it possible to produce silanol compounds at excellent yield. A composition comprising 5 mass % to 100 mass % of a silanol compound represented by Formulas (A) to (C) can be prepared by devising to produce silanol compounds under water-free conditions, to produce silanol compounds in a solvent having the effect of suppressing the condensation of silanol compounds, and to perform other such processes, the composition being able to be used as a raw material or the like of siloxane compounds because the silanol compounds can be stably present in the resulting composition.
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Paragraph 0214; 0215; 0218; 0219; 0220; 0221; 0222; 0223
(2017/07/14)
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- Fiber-Treating Agent
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The present invention relates to a fiber-treating agent having a pH value of 2 to 5 at 20° C. and containing an alkoxysilane (a), an organic acid (b) and water (c), wherein 50% or more by weight of the component (a) is an alkoxysilane represented by the following formula (1): R1pSi (OR2)4-p (1) wherein R1 represents a C1 to C6 alkyl group, a phenyl group, or a C2 to C6 alkenyl group, R2 represents a C1 to C6 alkyl group, and p is an integer of 1 to 3, and the number of moles of the component (c) is 3 times or more as large as that of the component (a), as well as a method of treating fibers with the fiber-treating agent, and fibers treated by this method.
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Page/Page column 5-6
(2008/12/08)
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- Atmospheric degradation of volatile methyl-silicon compounds
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The current widespread use of poly(dimethylsiloxane)s (PDMS) in a broad range of applications leads to their release into soil environments where they degrade to monomeric products, primarily dimethylsilanediol, most of which enter the atmosphere by volatilization. The major degradation pathway of volatile organosilicon compounds in the atmosphere is expected to be a reaction with hydroxyl (OH) radicals. In this work, the kinetics of the gas- phase reactions of dimethylsilanediol, trimethylsilanol, and tetramethylsilane with the OH radical were measured using a relative rate method which employed the N2H4 + O3 reaction as a nonphotolytic source of OH radicals, with analysis by Fourier transform infrared (FT-IR) spectroscopy in a 5870 L chamber. The measured values of the OH radical reaction rate constants (cm3 molecule-1 s-1) at 298 ± 2 K are as follows: dimethylsilanediol, (8.1 ± 1.0) x 10-13; trimethylsilanol, (7.2 ± 0.8) x 10-13; and tetramethylsilane, (8.5 ± 0.9) x 10-13. These values lead to an estimate of tropospheric lifetimes with respect to reaction with the OH radical of ca. 15 days for these organosilicon compounds. FT-IR spectroscopy and atmospheric pressure ionization mass spectrometry (API-MS) were employed to analyze the products of OH radical- and Cl atom-initiated photooxidations of dimethylsilanediol and trimethylsilanol. Infrared signatures of the probable formate ester intermediate products from both silanols were detected. API-MS analyses indicated the formation of methylsilanetriol from dimethylsilanediol, of both dimethylsilanediol and methylsilanetriol from trimethylsilanol, and of the corresponding intermediate formate esters. Possible reaction mechanisms are discussed. The current widespread use of poly(dimethylsiloxane)s (PDMS) in a broad range of applications leads to their release into soil environments where they degrade to monomeric products, primarily dimethylsilanediol, most of which enter the atmosphere by volatilization. The major degradation pathway of volatile organosilicon compounds in the atmosphere is expected to be a reaction with hydroxyl (OH) radicals. In this work, the kinetics of the gas-phase reactions of dimethylsilanediol, trimethylsilanol, and tetramethylsilane with the OH radical were measured using a relative rate method which employed the N2H4 + O3 reaction as a nonphotolytic source of OH radicals, with analysis by Fourier transform infrared (FT-IR) spectroscopy in a 5870 L chamber. The measured values of the OH radical reaction rate constants (cm3 molecule-1 s-1) at 298 ± 2 K are as follows: dimethylsilanediol, (8.1 ± 1.0) × 10-13; trimethylsilanol, (7.2 ± 0.8) × 1013; and tetramethylsilane, (8.5 ± 0.9) × 10-13. These values lead to an estimate of tropospheric lifetimes with respect to reaction with the OH radical of ca. 15 days for these organosilicon compounds. FT-IR spectroscopy and atmospheric pressure ionization mass spectrometry (API-MS) were employed to analyze the products of OH radical- and Cl atom-initiated photooxidations of dimethylsilanediol and trimethylsilanol. Infrared signatures of the probable formate ester intermediate products from both silanols were detected. API-MS analyses indicated the formation of methylsilanetriol from dimethylsilanediol, of both dimethylsilanediol and methylsilanetriol from trimethylsilanol, and of the corresponding intermediate formate esters. Possible reaction mechanisms are discussed.
- Tuazon, Ernesto C.,Aschmann, Sara M.,Atkinson, Roger
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p. 1970 - 1976
(2007/10/03)
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- Base Cleavage of the Benzyl-Silicon Bonds in m-ClC6H4CH2SiMe(OH)2 and m-ClC6H4CH2Si(OH)3. Proposed Formation of Metasilicate Intermediates
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A kinetic study of the base-catalysed cleavage of the diol RSiMe(OH)2 (R = m-ClC6H4CH2) in Me2SO-H2O or MeOH-H2O has indicated that at high base concentrations the main process is the unimolecular dissociation of the dianion RSiMe(O-)2 into R- and Me(O-)Si=O (an analogue of acetate ion), both of which then react rapidly with the solvent.Likewise for the triol RSi(OH)3 in Me2SO-H2O the main process appears to be the formation of R- and the metasilicate ion HO(O-)Si=O from the dianion R(OH)Si(O-)2.Base cleavage of the silanols RSiMe2OH (R = PhCH2 or m-ClC6H4CH2) in Me2SO-H2O probably involves a contribution from the unimolecular dissociation of the anion RSiMe2O- to give R- and Me2Si=O.
- Chmielecka, Jadwiga,Chojnowski, Julian,Stanczyk, Wlogdzimierz A.,Eaborn, Colin
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p. 865 - 872
(2007/10/02)
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- Evidence for Generation of the Unsaturated Sila-acetate Species Me(O-)Si=O by Dissociation of the Silanediolate Dianion m-ClC6H4CH2SiMe(O-)2
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Kinetic studies indicate that in the cleavage of m-ClC6H4CH2SiMe(OH)2 by NaOH in Me2SO-H2O there is a major contribution by unimolecular dissociation of the dianion m-ClC6H4CH2SiMe(O-)2 to give the acetate ion analogue Me(O-)Si=O.
- Chmielecka, Jadwiga,Chojnowski, Julian,Eaborn, Colin,Stancyzk, Wlodimierz A.
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p. 1337 - 1338
(2007/10/02)
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- SYNTHESIS AND REACTIONS OF SOME PERFLUOROALKYL ETHER SUBSTITUTED SILANES
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Perfluoroalkyl ether substituted silicon compounds of the type (CH3)nSi(RfORf)4-n (n=1-3) and HSi(RfORf)3 where RfORf=F(CF3)2COCF2CF2have been synthesized in good yields (64-81percent) through the reaction between the organolithium reagent RfORfLi and the corresponding silicon chloride.The stability of these compounds towards acid, base and aqueous media were studied and the ease of cleavage of the Si-RfORf bond was found to be in the order HSi(RfORf)3>CH3Si(RfORf)3>(CH3)2Si(RfORf)2>(CH3)3SiRfORf.The influence of the RfORf group on some properties of these compounds is also described.
- Chen, Grace J.,Tamborsky, Christ
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p. 313 - 322
(2007/10/02)
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