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Synthetic Air (synthetic + air)
Selected AbstractsAtmospheric Pressure Plasma Treatment of Glass Fibre Composite for Adhesion ImprovementPLASMA PROCESSES AND POLYMERS, Issue S1 2007Yukihiro Kusano Abstract Glass-fibre-reinforced polyester composite plates were treated with an atmospheric pressure dielectric barrier discharge. Synthetic air was used as the treatment gas. The water contact angle dropped markedly from 84 to 22° after a 2-s treatment, and decreased to 0° when the composite plates were treated for more than 30 s. X-Ray photoelectron spectroscopic analysis showed that the contents of aluminium and oxygen on the surface increased with the plasma treatment. The adhesion strength of the 2-s treated surface was comparable to or higher than that achieved by conventional mechanical surface roughening. It decreased when the surfaces were treated for 5 and 15 s, but recovered for 30-s treatment. [source] Kinetics of the gas-phase reaction of n -C6,C10 aldehydes with the nitrate radicalINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 3 2003Jun Noda Rate coefficients for gas-phase reaction between nitrate radicals and the n -C6,C10 aldehydes have been determined by a relative rate technique. All experiments were carried out at 297 ± 2 K, 1020 ± 10 mbar and using synthetic air or nitrogen as the bath gas. The experiments were made with a collapsible sampling bag as reaction chamber, employing solid-phase micro extraction for sampling and gas chromatography/flame ionization detection for analysis of the reaction mixtures. One limited set of experiments was carried out using a glass reactor and long-path FTIR spectroscopy. The results show good agreement between the different techniques and conditions employed as well as with previous studies (where available). With butanal as reference compound, the determined values (in units of 10,14 cm3 molecule,1 s,1) for each of the aldehydes were as follows: hexanal, 1.7 ± 0.1; heptanal, 2.1 ± 0.3; octanal, 1.5 ± 0.2; nonanal, 1.8 ± 0.2; and decanal, 2.2 ± 0.4. With propene as reference compound, the determined rate coefficients were as follows: heptanal, 1.9 ± 0.2; octanal, 2.0 ± 0.3; and nonanal, 2.2 ± 0.3. With 1-butene as reference compound, the rate coefficients for hexanal and heptanal were 1.6 ± 0.2 and 1.8 ± 0.1, respectively. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 35: 120,129, 2003 [source] Influence of relative gas humidity on the inactivation efficiency of a low temperature gas plasmaJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2008P. Muranyi Abstract Aims:, To investigate the effect of relative gas humidity on the inactivation efficiency of a cascaded dielectric barrier discharge (CDBD) in air against Aspergillus niger and Bacillus subtilis spores on PET foils. Methods and Results:, The inactivation kinetics as a function of treatment time were determined using synthetic air with different relative humidity as the process gas. Spores of A. niger and B. subtilis respectively were evenly sprayed on PET foils for use as bioindicators. In the case of A. niger, increased spore mortality was found at a high relative gas humidity of 70% (approx. 2 log10). This effect was more evident at prolonged treatment times. In contrast, B. subtilis showed slightly poorer inactivation at high gas humidity. Conclusions:, Water molecules in the process gas significantly affect the inactivation efficiency of CDBD in air. Significance and Impact of the Study:, Modifying simple process parameters such as the relative gas humidity can be used to optimize plasma treatment to improve inactivation of resistant micro-organisms such as conidiospores of A. niger. [source] Dehydration of benzene through fluorine containing aromatic polyamide membrane by pervaporationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008P. K. Gutch Abstract A series of soluble polyamides were synthesized by direct polycondensation of the 5- tert -butyl isophthalic acid with different diamines. Solution (20%) of the polymers in suitable solvents was used to cast the membranes. The membranes showed selectivity toward the benzene (Bz) in a mixture of Bz/water (H2O). Water affinity of the membrane was found to be lower than that of Bz. The polyamide incorporating hexafluoro isopropylidene moiety was promising for the dehydaration of Bz and breaking of Bz/H2O azeotrope. The polymers exhibited inherent viscosities, ranging from 0.40 to 0.92 dL/g and 10% weight loss in synthetic air up to 474°C. Glass transition temperature measured by DSC and DMA reached up to 258°C. The membranes were pale yellow in appearance having tensile strength up to 85 MPa, modulus of elasticity up to 2.6 GPa, and elongation at break up to 9.5%, depending upon the exact repeating unit structure. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Synthesis and characterization of novel poly(arylene ether)s based on 9,10-bis-(4-fluoro-3-trifluoromethylphenyl) anthracene and 2,7-bis-(4-fluoro-3-trifluoromethylphenyl) fluoreneJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007Arun K. Salunke Abstract Two new bisfluoro monomers 9,10-bis-(4-fluoro-3-trifluoromethylphenyl) anthracene and 2,7-bis-(4-fluoro-3-trifluoromethylphenyl) fluorene have been synthesized by the cross-coupling reaction of 2-fluoro-3-trifluoromethyl phenyl boronic acid with 9,10-dibromo anthracene and 2,7-dibromo fluorine, respectively. These two bisfluoro compounds were used to prepare several poly(arylene ether)s by aromatic nucleophilic displacement of fluorine with various bisphenols; such as bisphenol-A, bisphenol-6F, bishydroxy biphenyl, and 9,9-bis-(4-hydroxyphenyl)-fluorene. The products obtained by displacement of the fluorine atoms exhibits weight-average molar masses up to 1.5 ×105 g mol,1 and number average molecular weight up to 6.8 × 104 g mol,1 in GPC. These poly(arylene ether)s show very high thermal stability even up to 490°C for 5% weight loss occurring at this temperature in TGA in synthetic air and showed glass transition temperature observed up to 310°C. All the polymers are soluble in a wide range of organic solvents, e.g., CHCl3, THF, NMP, and DMF. Films cast from DMF solution are brittle in nature. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 [source] CH3CH2SCH3,+,OH radicals: temperature-dependent rate coefficient and product identification under atmospheric pressure of air,JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 10 2010Gabriela Oksdath-Mansilla Abstract Relative rate coefficients have been determined for the gas-phase reaction of hydroxyl (OH) radicals with ethyl methyl sulfide (EMS) using isobutene as a reference compound. The experiments were performed in a 1080,L quartz glass photoreactor in the temperature range of 286,313,K at a total pressure of 760,±,10,Torr synthetic air using in situ FTIR absorption spectroscopy to monitor the concentration-time behaviors of reactants and products. OH radicals were produced by the 254,nm photolysis of hydrogen peroxide (H2O2). The kinetic data obtained were used to derive the following Arrhenius expression valid in the temperature range of 286,313,K (in units of cm3,molecule,1,s,1): The rate coefficient displays a negative temperature dependence and low pre-exponential factor which supports the existence of an addition mechanism for the reaction involving reversible OH-adduct formation. The results are compared with previous data of other sulfides from the literature and are rationalized in terms of structure,reactivity relationships. Additionally, product identification of the title reaction was performed for the first time by the FTIR technique under atmospheric conditions. Sulfur dioxide, formaldehyde, and formic acid were observed as degradation products in agreement with the two possible reaction channels (addition/abstraction). Copyright © 2010 John Wiley & Sons, Ltd. [source] Gas-phase reactions of Cl atoms with hydrochloroethers: relative rate constants and their correlation with substituents' electronegativitiesJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 5 2008Pablo R. Dalmasso Abstract Rate constants for the reactions of Cl atoms with CH3OCHCl2 and CH3OCH2CH2Cl were determined at (296,±,2) K and atmospheric pressure using synthetic air as bath gas. Decay rates of these organic compounds were measured relative to the following reference compounds: CH2ClCH2Cl and n -C5H12. Using rate constants of 1.33,×,10,12 and 2.52,×,10,10,cm3,molecule,1,sec,1 for the reaction of Cl atoms with CH2ClCH2Cl and n -C5H12, respectively, the following rate coefficients were derived: k(Cl,+,CH3OCHCl2),=,(1.05,±,0.11),×,10,12 and k(Cl,+,CH3OCH2CH2Cl),=, (1.14,±,0.10),×,10,10, in units of cm3,molecule,1,s,1. The rate constants obtained were compared with previous literature data and a correlation was found between the rate coefficients of some CH3OCHR1R2,+,Cl reactions and ,Electronegativity of CHR1R2. Copyright © 2008 John Wiley & Sons, Ltd. [source] Synthesis and characterization of poly(arylene ether)s derived from 4,4,-bishydroxybiphenyl and 4,4,-bishydroxyterphenylJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2002Arun Kashinath Salunke Abstract A series of poly(arylene ether)s were successfully prepared by aromatic, nucleophilic substitution reactions with various perfluoroalkyl-activated bisfluoromonomers with 4,4,-bishydroxybiphenyl and 4,4,-bishydroxyterphenyl. 4,4,-Bishydroxyterphenyl was synthesized through the Grignard coupling reaction of magnesium salt of 4-bromoanisole with dibromobenzene followed by demethylation with pyridine,hydrochloride. The products obtained by the displacement of fluorine atoms exhibited good inherent viscosity, up to 0.77 dL/g, and number-average molecular weights up to 69,300. These poly(arylene ether)s showed very good thermal stability, up to 548 °C for 5% weight loss according to thermogravimetric analysis under synthetic air, and high glass-transition temperatures, up to 259 °C according to differential scanning calorimetry, depending on the exact repeat unit structure. These polymers were soluble in a wide range of organic solvents, such as N -methylpyrrolidone, dimethylformamide, tetrahydrofuran, toluene, and CHCl3, and were insoluble in dimethyl sulfoxide and acetone. Thin films of these poly(arylene ether)s showed good transparency and exhibited tensile strengths up to 132 MPa, moduli up to 3.34 GPa, and elongations at break up to 84%, depending on their exact repeating unit structures. These values are comparable to those of high-performance thermoplastic materials such as poly(ether ether ketone) (PEEK) and Ultem poly(ether imide) (PEI). These poly(arylene ether)s exhibited low dielectric constants. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 55,69, 2002 [source] Physical adsorption vs. chemical binding of undecylenic acid on porous silicon surface: a comparative study of differently functionalized materialsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2009E. Pastor Abstract To imply miscibility to porous silicon (PSi) used for biomedical purposes a number of functionalization methods are employed. In order to distinguish between a non-specific surfactant-like interaction (physical sorption) and chemical binding of unsaturated chemicals (undecylenic acid, UD) to H-terminated PSi surface we studied the two differently treated materials. Differential scanning calorimetry (DSC) and thermogravimetry (TGA), BET and FTIR measurements were performed with the PSi powder samples (n+ doped). Changes in surface area, weight loss, calorific effect and chemical composition that accompanied the thermal treatment have shown that the physisorbed UD molecules undergo a chemical process (binding) with the Si-Hx surface groups at about 150 °C in both, N2 inert atmosphere and in a synthetic air, oxidative atmosphere. Controlled conversion of physically sorbed molecules to the chemically attached ones is discussed with respect to methods of surface modification of PSi materials for increasing their biocompatibility. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||