The Experts below are selected from a list of 228 Experts worldwide ranked by ideXlab platform
Ung Su Choi - One of the best experts on this subject based on the ideXlab platform.
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Fourier Transform Infrared Spectroscopy Study on Cation adsorption on Viscose Rayon Succinate
Mongolian Journal of Chemistry, 2014Co-Authors: D Khasbaatar, Ung Su ChoiAbstract:Ion-exchange materials have been considered as suitable material for the recovery of heavy metals in water. A viscose Rayon succinate, synthesized from viscose Rayon and succinic anhydride in presence of DMSO, to remove trace bivalent metal ions such as Ag + , Cu 2+ , Ni 2+ , Pb 2+ , Zn 2+ and Cr 3+ , was studied using FT-IR for the behavior of metal adsorption. Both esterification and carboxyl bonding of viscose Rayon succinate were assigned essentially at 1729 and 1693cm -1 , respectively. And the essential band of bonding between metal and the material was determined at 1625cm -1 . The available adsorption capacity of this fiber was 6.2 mequiv/g. The adsorption of metal ions on the viscose Rayon succinate follows the order of Cu 2+ >Cr 3+ >Ni 2+ >Pb 2+ >Zn 2+ >Ag + with maximum adsorptions capacities 4.2, 1.42, 0.91, 0.83, 0.69 and 0.35 mmol/g, respectively. DOI: http://dx.doi.org/10.5564/mjc.v12i0.189 Mongolian Journal of Chemistry Vol.12 2011: 136-141
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Physicochemical and Thermal Properties of Viscose Rayon Borate Felt
Journal of Industrial and Engineering Chemistry, 2001Co-Authors: Young Gun Ko, Ung Su ChoiAbstract:Berate, as a multifunctional material that is a flame retardant, smoke suppressant, afterglow suppressant and electrically resistant, was synthesized on viscose Rayon felt using surface modification reactions. In addition viscose Rayon phosphate was also synthesized for a comparison test. All reactions were confirmed by ATR FT-IR and TOF-SIMS. The thermal properties of the synthesized viscose Rayon berates were investigated using a thermogravimetric analysis and calculated activation energy using the Freeman and Carroll method. The optimal reaction temperature of the synthesized viscose Rayon berate was found to be 350 ℃. Oxygen index and volumetric resistance rate tests of viscose Rayon berate were conducted for flame retardency and electrical resistance, and compared with viscose Rayon phosphate, The synthesized viscose Rayon berate showed excellent physicochemical and thermal properties, and was found to be a highly effective flame retardant and electrically resistant.
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Physicochemical and thermal studies of viscose Rayon borate fiber and its carbon fiber
Journal of Polymer Science Part A, 2001Co-Authors: Young Gun Ko, Ung Su ChoiAbstract:Nonhalogen compounds have been studied for improvements in the flameproofing property and toxicity of flame retardants. Borate compounds have properties of multifunctional smoke suppressants, flame retardants, and afterglow suppressants. In this study, borate was coupled onto the surface of viscose Rayon felt. Coupling and carbonization were confirmed by attenuated total reflectance Fourier transform infrared (ATR FTIR). The initial carbonization temperature was certified with ATR FTIR, elemental analysis of carbon, and thermogravimetric analysis. In the carbonization step, all chemical groups of the surface of the viscose Rayon felt degraded to the various gases. Moreover, the weight percentage of the carbon element increased with increasing carbonization temperature. Initial rapid thermal degradation temperatures of viscose Rayon prepared at various temperatures increased with the increasing reaction temperature. The activation energy was calculated with the Freeman and Carroll method. The activation energy of borate-coupled viscose Rayon decreased much more than before coupling. However, the activation energy increased with the increasing carbonization temperature in the carbonization step. Viscose Rayon borates showed higher limiting oxygen index (LOI) values and volumetric resistance rate values than viscose Rayon phosphates. In this article, the relationship between the activation energy and LOI is studied. The synthesized viscose Rayon borate is found to be highly effective as a flame retardant and electrically resistant.
Marek Smieja - One of the best experts on this subject based on the ideXlab platform.
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comparison of flocked and Rayon swabs for collection of respiratory epithelial cells from uninfected volunteers and symptomatic patients
Journal of Clinical Microbiology, 2006Co-Authors: Peter Daley, Santina Castriciano, Max Chernesky, Marek SmiejaAbstract:Significantly more epithelial cells were collected by flocked swabs than by Rayon swabs in parallel nasopharyngeal and nasal swabs taken from 16 volunteers. Nasopharyngeal sampling of 61 symptomatic patients also yielded more cells by flocked than Rayon swabs, providing better clinical specimens for diagnosis.
Yonggang Yang - One of the best experts on this subject based on the ideXlab platform.
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a mechanism study on preparation of Rayon based carbon fibers with nh4 2so4 nh4cl organosilicon composite catalyst system
Composites Science and Technology, 2007Co-Authors: Hui Li, Yonggang YangAbstract:Abstract The mechanisms of the preparation of Rayon based carbon fibers with (NH 4 ) 2 SO 4 /NH 4 Cl/organosilicon composite catalyst system were studied. The thermal behaviors of Rayon fibers that were treated with different catalysts were studied by thermogravimetry–mass spectrometry (TG–MS) and the surface of treated Rayon fibers was studied by scanning electron microscopy (SEM) analysis. Our data showed that the composite catalyst treated Rayon fibers underwent pyrolysis under lower temperatures and in a wider range of temperatures. Rayon based carbon fibers prepared with different catalyst system showed different mechanical properties. The presence of (NH 4 ) 2 SO 4 /NH 4 Cl/organosilicon increased the production of H 2 O, CO 2 , CO and decreased the production of tar, aldehyde, furan and phenol derivatives. The composite catalyst also promoted the pyrolysis reaction of Rayon fibers by lowering its activation energy. Organosilicon seemed to have two aspects of effects on the process of preparing Rayon based carbon fibers. It could enhance the penetrability of (NH 4 ) 2 SO 4 /NH 4 Cl to the interior of Rayon fibers and protect the fiber surface in the pyrolysis process. Moreover, organosilicon may participate in the crosslinking reactions of Rayon fibers and enhance the drawability of Rayon fibers in carbonization process. Our experiments demonstrated that (NH 4 ) 2 SO 4 /NH 4 Cl/organosilicon was an effective composite catalyst system in the preparation of Rayon based carbon fibers.
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study on the pyrolysis of wood derived Rayon fiber by thermogravimetry mass spectrometry
Journal of Molecular Structure, 2005Co-Authors: Chunxiang Lv, Yonggang Yang, Fu He, Licheng LingAbstract:Abstract The thermal pyrolysis of wood-derived Rayon fiber has been studied from ambient temperature up to 800 °C by thermogravimetry–mass spectrometry (TG–MS) analysis in an inert environment. Following an initial plateau region, the wood-derived Rayon fiber rapidly decomposes in a narrow temperature range of 300–350 °C. After this sharp weight loss, there is a gradual but constant weight loss up to 800 °C. The values of kinetic parameters have been determined by using two dynamic thermogravimetric curves (TG and DTG). The data show that kinetics of wood-derived Rayon fiber is similar to that of other cellulosic materials thermal degradation. Gases and tarry volatile products formed from the pyrolysis of wood-derived Rayon fiber are monitored by MS. Water ( m/z 18) is the predominant ion observed, followed by CO ( m/z 28), CO 2 ( m/z 44) and CH 4 ( m/z 16). The MS signals show that the tarry volatiles are composed of varieties of compounds. The formation reactions of primary products from the pyrolysis are discussed in detail in the present paper.
M Y Yoon - One of the best experts on this subject based on the ideXlab platform.
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enzymatic hydrolysis of cotton linen ramie and viscose Rayon fabrics
Textile Research Journal, 1994Co-Authors: Gisela Buschlediller, S.h. Zeronian, M Y YoonAbstract:Cotton, linen, ramie, and viscose Rayon fabrics along with a cotton / linen blend were hydrolyzed with cellulase from Trichoderma viride. Surface fibrils were eliminated by a 6 hour treatment in all cases. The loss of fibrillar matter appeared to be the primary cause of weight loss at this stage. On prolonged treatment, cotton, linen, and viscose Rayon lost weight at a faster rate than ramie and the cotton / linen blend. The fall in yam strength was progressive with increasing weight loss for cotton and viscose, while for linen and ramie it was slight initially and then increased sharply. Retention of strength after 48 hours' incubation time increased in the order viscose Rayon << cotton < ramie < linen, whereas weight loss increased in the order ramie < linen < cotton < viscose Rayon. X-ray crystallinity and moisture sorption of the samples did not change after the treatment, indicating that the mechanism of endwise attack of the cellulase at accessiblc cellulose chains on crystallite surfaces appeared t...
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Enzymatic Hydrolysis of Cotton, Linen, Ramie, and Viscose Rayon Fabrics
Textile Research Journal, 1994Co-Authors: Gisela Buschle-diller, S.h. Zeronian, M Y YoonAbstract:Cotton, linen, ramie, and viscose Rayon fabrics along with a cotton / linen blend were hydrolyzed with cellulase from Trichoderma viride. Surface fibrils were eliminated by a 6 hour treatment in all cases. The loss of fibrillar matter appeared to be the primary cause of weight loss at this stage. On prolonged treatment, cotton, linen, and viscose Rayon lost weight at a faster rate than ramie and the cotton / linen blend. The fall in yam strength was progressive with increasing weight loss for cotton and viscose, while for linen and ramie it was slight initially and then increased sharply. Retention of strength after 48 hours' incubation time increased in the order viscose Rayon
Peter Daley - One of the best experts on this subject based on the ideXlab platform.
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comparison of flocked and Rayon swabs for collection of respiratory epithelial cells from uninfected volunteers and symptomatic patients
Journal of Clinical Microbiology, 2006Co-Authors: Peter Daley, Santina Castriciano, Max Chernesky, Marek SmiejaAbstract:Significantly more epithelial cells were collected by flocked swabs than by Rayon swabs in parallel nasopharyngeal and nasal swabs taken from 16 volunteers. Nasopharyngeal sampling of 61 symptomatic patients also yielded more cells by flocked than Rayon swabs, providing better clinical specimens for diagnosis.
