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Preparation and properties of PEG hydrogel from PEG macromonomer with sulfonate end group
Kim, Ji-Heung,Kim, Jun-Guk,Kim, Dukjoon,Kim, Young Ha Wiley Subscription Services, Inc., A Wiley Company 2005 Journal of applied polymer science Vol.96 No.1
<P>A novel PEG macromonomer with methacryloyl and sulfonate group at each chain end was prepared, and new PEG-based hydrogels were prepared by crosslinking polymerization of this PEG macromonomer in the presence of PEG dimethacrylate. Their swelling properties are measured and compared with those of reference hydrogel from methoxy PEG methacrylate to elucidate the effect of the sulfonate end group. The prepared sulfonated PEG hydrogels exhibited water absorbency in the range of 19 ∼ 42 g water/g dry-gel depending on the composition. These hydrogels with anionic sulfonate group showed swelling behavior varying with salt type, concentration, and also with pH of aqueous solution. The morphology of the sulfonated PEG gels by SEM showed irregular porous network structure varying with the composition. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 56–61, 2005</P>
Dukjoon Kim(김덕준) 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.1
Solid polymer electrolyte (SPE) was prepared from PAEK-g-PEG and PYR14-TFSI IL. Interfacial compatibility, lithium ion conductivity and transference number, thermal, mechanical and dimensional stability for lithium battery applications were investigated and correlated to ion cluster dimension examined by SAXS. The synthesized SPE illustrated thermal degradation temperature over 200 ℃, elongation at break of 250% and negligible dimensional change at 120 ℃. This flexible SPE exhibited the highest ion conductivity of ~ 1×10<sup>-3</sup> S cm<sup>-1</sup> at room temperature. As the active electrode materials such as LCO and NMC622 were quite compatible with SPE, the battery cells fabricated by binding the SPE and cathode layer showed excellent cell performance of 139.01 mAh g<sup>-1</sup> (LCO) and 158.15 mAh g<sup>-1</sup> (NMC 622) at 0.1 C. When this multi-functional SPE was applied to the lithium sulfur battery system, the cell discharge capacity was even higher than 925 mAh g<sup>-1</sup> at 0.1C with cyclic stability (>50 cycles).
Kim, Jusung,Kwak, Juho,Kim, Dukjoon Wiley Subscription Services, Inc., A Wiley Company 2007 Journal of applied polymer science Vol.106 No.6
<P>PMMA nanoparticles with highly mono-dispersed size distribution were prepared using the RAFT living radical emulsion polymerization technique. A novel sur-iniferter for the RAFT reaction, DTBA, was synthesized and its chemical structure was identified using several spectroscopic techniques. The relationship between the particle size and the molecular weight of the polymer was investigated measuring the rate of growth of each during formation of particles, and was well explained by the simple random flight molecular conformation model. The particle size increased up to a certain value with decreasing sur-iniferter concentration and then leveled off, because the surface charge density of the growing particles was not high enough to stabilize the particles in aqueous medium above that value. The core-shell type di-block copolymer nanoparticles were also successfully prepared via RAFT reaction. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007</P>
Kim, Jeong Hoon,Sim, Sang Jun,Lee, Dong Hyun,Kim, Dukjoon,Lee, Young Kwan,Kim, Ji-Heung 한국공업화학회 2004 Journal of Industrial and Engineering Chemistry Vol.10 No.2
α ,β -Poly(N-2-hydroxyethyl-DL-aspartamide), PHEA, one of 'the poly(amino acid)s having pendent hydroxyl groups, is biodegradable and biocompatible, and has been studied as a useful biomaterial, especially for drug delivery, by appropriate structural modification. In this work, PHEA, which we derived from polysuccinimide, was crosslinked by glutaraldehyde units in the presence of an acid catalyst to provide hydrogels with relatively good gel strength. The dry gels were formed into pressed discs, and their swelling behavior was investigated in different media under various conditions (pH, temperature, etc). In addition, we examined the hydrolytic degradation in aqueous solution. A porous scaffold was fabricated by freeze-drying the water-swollen gel; its morphology was observed by scanning electron microscopy. The PHEA-based hydrogels are potentially useful in biomedical applications; for example, as biodegradable matrices for DDS and tissue engineering.
Dukjoon Kim 한국막학회 1998 멤브레인 Vol.8 No.1
The study on penetrant transport in glassy polymers has been actively pursued for decades because of its growing significance in polymer processing and related applications such as not only membranes, but corrosion protective coatings, microlithography, microelectronic fabrication, etc. In membranes application of polymeric materials, successful utilization requires understanding of how solvents penetrate, swell, and sometimes dissolve polymeric materials under various environmental conditions, as their permselecdve performance is significantly affected by it. The expose of polymer membranes to solvents may result in the structural failure due to mechanical softening, embrittlement or crazing.
Kim, Nayoung,Kim, Dukjoon Elsevier 2009 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.34 No.19
<P><B>Abstract</B></P><P>The SO<SUB>2</SUB> transport properties of Nafion<SUP>®</SUP> and sPEEK membranes were measured using an electrochemical reaction cell to investigate their application in the electrochemical hybrid sulfur process. The permeability of SO<SUB>2</SUB> in the membranes was determined from a combined theory based on Faraday's law and Fick's law where the electrochemical reaction rate of SO<SUB>2</SUB> in the downstream membrane is the same as its diffusion flux through the membrane. Both Nafion<SUP>®</SUP> and sPEEK membranes show higher SO<SUB>2</SUB> diffusion coefficients at higher temperatures. For sPEEK membranes, increasing the degree of sulfonation resulted in increasing permeability, as more water was imbibed in the membranes with higher degrees of sulfonation. Activation energy was extracted from the temperature-dependence of the diffusion coefficients for both membranes. The sPEEK membranes exhibited similar diffusion coefficients to those of Nafion<SUP>®</SUP>, even at high sulfonation degrees of 70%. Besides SO<SUB>2</SUB> permeability, proton conductivity and mechanical properties were measured for comparison between the 2 polymer membranes. Although the proton conductivity of the sPEEK was slightly lower than the Nafion<SUP>®</SUP> membrane, it was very competitive considering its higher mechanical strength and much lower cost.</P>
Barrier Property and Morphology of Polypropylene/Polyamide Blend Film
Kim, Dukjoon,Kim, Seong Woo 한국화학공학회 2003 Korean Journal of Chemical Engineering Vol.20 No.4
The barrier property of polypropylene (PP)/polyamide (PA) blend film produced by the extrusion casting film process was studied by investigating the effects of rheological properties of each components, compatibilizer content, screw rpm, and the absorbed moisture, and by performing morphological analysis and permeability modeling. The oxygen barrier property of blend film with ellipsoidal structure of PA dispersed phase was significantly improved by a factor of 5.4 with the addition of only 20 wt% PA, when compatibilizer was added by the content of 7 phr and the PP matrix resin and process condition was selected to induce lower viscosity ratio less than unity. Using Fricke’s model with the value of 19.6 of aspect ratio of the ellipsoid, the permeabilities of blend films as a function of PA content could be predicted and exhibited a good agreement with the experimental results. The absorbed moisture had a significant influence on the barrier property of the PP/PA blend system, suggesting that the hygroscopic P resin should be incorporated with the high water barrier PP resin by the amount below about 20 wt% to minimize the deterioration of the barrier property in the humid atmosphere.