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Daejeon, South Korea

Ko K.-H.,Chosun University | Park H.R.,Chosun University | Kim J.-S.,Chosun University | Kim Y.-W.,Green Chemistry Research Division
Journal of Applied Polymer Science | Year: 2013

The effects of the presence of dimer acid (DA) molecules in Na-sulfonated polystyrene (PSSNa) and poly(styrene-co Na-methacrylate) (PSMANa) ionomers on the ionomer properties were investigated using a dynamic mechanical analysis technique. The DA decreased the matrix and cluster Tgs of PSSNa ionomer without changing the ionic modulus, suggesting that the DA resided both in the matrix and cluster regions of PSSNa ionomer and acted mainly as a plasticizer. On the other hand, the DA decreased the cluster Tg of PSMANa ionomer, without changing the matrix Tg, and also increased the ionic modulus, implying that the DA behaved like plasticizer only for the cluster regions. Copyright © 2013 Wiley Periodicals, Inc. Source

Lee S.-H.,Korea Institute of Energy Research | Heo H.S.,University of Seoul | Jeong K.-E.,Green Chemistry Research Division | Yim J.-H.,Kongju National University | And 5 more authors.
Journal of Nanoscience and Nanotechnology | Year: 2011

The catalytic cracking of oilsand bitumen was performed over nanoporous materials at atmospheric conditions. The yield of gas increased with application of nanoporous catalysts, with the catalytic conversion to gas highest for Meso-MFI. The cracking activity seemed to correlate with pore size rather than weak acidity or surface area. Copyright © 2011 American Scientific Publishers. Source

Park H.J.,University of Seoul | Heo H.S.,University of Seoul | Jeon J.-K.,Kongju National University | Kim J.,Korea Advanced Institute of Science and Technology | And 3 more authors.
Applied Catalysis B: Environmental | Year: 2010

The catalytic upgrading of pyrolytic vapors derived from radiata pine sawdust was carried out over mesoporous MFI zeolite synthesized using an amphiphilic organosilane. Its catalytic activity was compared with those of conventional HZSM-5 and mesoporous material from HZSM-5 (MMZZSM-5). The effect of gallium incorporation into mesoporous MFI zeolite on the product distribution and chemical composition of bio-oil was also investigated. The catalysts synthesized were characterized using ICP, XRD, N2-sorption, NH3-TPD, and H2-TPR methods. After catalytic upgrading, products were analyzed by GC-TCD, GC-FID, GC-MS, and Karl Fischer titration. The mesoporous MFI zeolite exhibited the best activity in deoxygenation and aromatization during the upgrading of pyrolytic vapors. In particular, mesoporous MFI zeolite showed high selectivity for highly valuable aromatics, such as benzene, toluene, and xylenes (BTX), even though it decreased the overall organic fraction of the bio-oil. The incorporation of gallium into the mesoporous MFI zeolite increased both the organic fraction of the bio-oil and resistance to coke deposition. Moreover, the selectivity for BTX aromatics was enhanced when the appropriate amount of gallium was introduced. © 2010 Elsevier B.V. All rights reserved. Source

Park J.H.,University of Seoul | Heo H.S.,University of Seoul | Park Y.-K.,University of Seoul | Jeong K.-E.,Green Chemistry Research Division | And 4 more authors.
Korean Journal of Chemical Engineering | Year: 2010

A variety of SAPO-34 catalysts were prepared using various templates, such as tetraethylammonium hydroxide (TEAOH), diethylamine (DEA), and a mixture of TEAOH and DEA, and then applied for the first time to the pyrolysis of high-density polyethylene (HDPE). The crystal morphology and physicochemical properties were affected by the type of template employed. In particular, an inexpensive SAPO-34 catalyst, with good crystal properties and catalytic performance, was obtained using a mixed-template of DEA and TEAOH. Through N2 isotherm, XRD, SEM and NH3 TPD the effects of the mixed-template on the crystal morphology and acidity were investigated. The catalytic activity of SAPO-34 in the pyrolysis of HDPE was improved with the use of a mixed-template, due to the crystal size, surface area and acidity. Source

Rode A.B.,Kongju National University | Thajudeen H.,Kongju National University | Chung K.,Green Chemistry Research Division | Kim Y.-W.,Green Chemistry Research Division | Hong I.S.,Kongju National University
Bulletin of the Korean Chemical Society | Year: 2011

1,2,4,5-tetraoxane, mono and dinitrate glycerol carbonate ester derivatives of stearic acid were synthesized along with the known 9(10)-keto methyl sterate, methoxy mono-nitrate and dinitrate of methyl stearate. Their cetane numbers (CNs) were investigated to evaluate their viability for use as CN improvers. The CN performances of tetraoxane and all of the nitrate derivatives were investigated at 500 and 1000 ppm concentrations and compared to that of a traditional CN improver 2-ethylhexyl nitrate (2-EHN). The experimental results suggest that all derivatives evaluated in this study showed better CN improvement than base diesel fuel. Specifically, the 1,2,4,5-tetraoxane derivative of stearic methyl ester was superior to all derivatives studied, also being superior to 2-EHN. We also discussed the correlations between the observed CN trends and thermo-analytical data resulted from thermo gravimetric analysis curves (TGA) and differential scanning calorimetry (DSC). Source

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