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Vennerberg D.C.,Iowa State University | Quirino R.L.,Iowa State University | Jang Y.,Kumho Petrochemical R and Center | Kessler M.R.,Iowa State University | Kessler M.R.,Washington State University
ACS Applied Materials and Interfaces | Year: 2014

Multiwalled carbon nanotubes (MWCNTs) were simultaneously fluidized and oxidized with gaseous ozone in a vertical reactor. Two different varieties of MWCNTs were compared to determine the versatility of the treatment and to elucidate the effect of defects on the oxidation behavior of MWCNTs. The extent of oxidation and nature of functional groups introduced on the nanotube surfaces were determined using Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and Boehm titration, and structural changes were monitored with Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). After only a few minutes of treatment, nongraphitic impurities were removed from the MWCNTs, and significant levels of oxidation (∼8 atom % O) were achieved with very little damage to the nanotube sidewalls. Short O3 exposure resulted in primarily hydroxyl functionalities, whereas longer exposure led to the formation of mainly carboxylic acid groups. Aliphatic defects present in the commercially produced MWCNTs were found to play an important role in the oxidation mechanism. Because of its ability to remove impurities and to evenly oxidize the sidewalls of nanotubes without the use of any solvents, the fluidized O3 reaction developed in this study was found to be an attractive option for industrial-scale MWCNT functionalization. © 2014 American Chemical Society. Source

Kim Y.M.,Kumho Petrochemical R and Center | Oh S.G.,Sungkyunkwan University | Kim D.,Kongju National University | Cho J.,Kongju National University
Asian Journal of Chemistry | Year: 2014

Herein, iso baric vapor-liquid phase equilibrium experiments for the binary mixture of di-n-propyl ether and 1-propanol were performed at 1.013 and 300 mbar. respectively. At 1,013 mbar. an azeotrope was formed where the mole composition of di-n-propyl ether is 0.6472 with azeotropic temperature of 90.18 °C. On the other hand, at 300 mbar. an azeotrope was formed with a mole composition of 0.7682 mole fraction of di-n-propyl ether and an azeotropic temperature of 52,61 °C. Througltout these vapor-liquid phase equilibrium experiments, it was observed that the azeotropic point of the di-n-propyl ether/1-propanol binary system changes with the system pressure. By conducting a regression analysis of the binary vapor-liquid phase equilibrium experimental data using liquid activity coefficients thermodynamics (LACT) models, such as UNIQUAC. NRTL and Wilson embedded in PRO/II with PROVISION 9.1, a commercial chemical process simulator from Invensys. Inc, optimum binary interaction parameters for the individual model equations were determined. This work lead to the generation of binary interaction parameters that better fit the experimental data parameter embedded in the PRO/II simulator. Source

Park J.-H.,Chungbuk National University | Noh H.,Kumho Petrochemical R and Center | Park J.W.,Kumho Petrochemical R and Center | Row K.H.,Kumho Petrochemical R and Center | And 2 more authors.
Research on Chemical Intermediates | Year: 2011

A series of BiMoFe0.65Px oxide catalysts with varying phosphorous contents from 0.0 to 0.6 mol ratio were prepared by a co-precipitation method, and oxidative dehydrogenation (ODH) was carried out to produce 1,3-butadiene (BD) from n-butenes. The physico-chemical properties of the oxide catalysts were characterized by X-ray diffraction (XRD), Raman spectroscopy, N2 sorption, and NH3 and 1-butene temperature-programmed desorption (TPD). Among the catalysts studied here, BiMoFe0.65P0.1 oxide catalyst showed the highest conversion and selectivity to BD. From the result of 1-butene TPD, the higher catalytic activity is related to the amount of weakly bounded intermediate and the desorbing temperature of strongly bounded intermediates. Also, the higher catalytic activity likely originates from the acidity of the BiMoFe 0.65P0.1 oxide catalyst; its acidity was higher than that of phosphorous-free oxide catalyst and further contained other oxide catalysts. BiMoFe0.65P0.1 oxide catalyst is stable and no significant deactivation for 100 h ODH reaction was shown. © 2011 Springer Science+Business Media B.V. Source

Lee J.-Y.,Pusan National University | Lee J.-Y.,Kumho Petrochemical R and Center | Lee T.,Pusan National University | Kim K.,Pusan National University | And 6 more authors.
Polymer International | Year: 2014

To improve the dispersion of silica in silica-filled styrene-butadiene rubber tire tread compounds, we synthesized poly(styrene-r-butadiene)-b-poly(poly(ethylene glycol) methyl ether methacrylate) (p(SB-b-PEGMA)) as a silica dispersant. p(SB-b-PEGMA) was synthesized by combining living anionic polymerization (LAP) and atom transfer radical polymerization (ATRP). Initially, α-bromoisobutyryl-terminated poly(styrene-r-butadiene) (pSB-Br) was prepared by LAP of styrene and butadiene and sequential additions of ethylene oxide and α-bromoisobutyryl bromide. pSB-Br was then used as the macroinitiator in the ATRP of PEGMA (Mn=300 gmol-1). The structure of p(SB-b-PEGMA) was characterized using gel permeation chromatography and 1H NMR spectroscopy. The application of p(SB-b-PEGMA) as a silica dispersant in styrene-butadiene rubber/silica decreased the optimal vulcanization time and improved the mechanical properties, which included 100% and 300% moduli, crosslinking density and silica dispersion. © 2013 Society of Chemical Industry. Source

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