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Seoul, South Korea

Mokpo National University is a national university located in Muan and Mokpo, South Korea. Wikipedia.

Rhim J.-W.,Mokpo National University
Carbohydrate Polymers | Year: 2011

Agar/clay (Cloisite Na +) nanocomposite films with different amount of the nanoclay (0, 2.5, 5, 10, 15, and 20 g clay/100 g agar) were prepared using a solution intercalation method. Results on X-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed well developed intercalated nanocomposite films especially at low level of nanoclay addition, and their properties were greatly influenced with the clay content. Tensile strength (TS) increased with increase in the clay content up to 10%, and decreased with more than 10% of clay incorporation. Water vapor permeability (WVP), water vapor uptake ratio (WVUR 5), and water solubility (WS) decreased with increase in the nanoclay content due to the tortuous path for water vapor diffusion and strong structure formed between the intercalated silicate layers and the polymer matrix. Hydrophilicity of the nanocomposite films increased with increase in the hydrophilic nanoclay, resulted in decreased water contact angle (CA) and increased swelling ratio (SR). © 2011 Elsevier Ltd All rights reserved.

Yoon C.,Mokpo National University
Computers in Human Behavior | Year: 2011

This paper proposes an ethical decision-making model in the Internet context based on moral theories and then empirically tests the model. The model posits that five moral philosophy variables - justice, relativism, egoism, deontology, and utilitarianism - affect ethical judgment; ethical judgment, in turn, affects behavioral intentions. To empirically test the model, four scenarios, real-life situations containing an ethical dilemma on the Internet, were developed and empirically analyzed by structural equation modeling with data from 111 university students. The results showed the five moral philosophy variables affected ethical judgment, each having different effects according to the particular ethical situation. Also, justice, utilitarianism, and ethical judgment were found to influence behavioral intentions in ethical dilemma situations on the Internet. © 2011 Elsevier Ltd. All rights reserved.

Kim S.C.,Mokpo National University | Shim W.G.,Chonnam National University
Applied Catalysis B: Environmental | Year: 2010

Catalytic combustion of volatile organic compounds (VOCs: benzene and toluene) was studied over manganese oxide catalysts (Mn3O4, Mn2O3 and MnO2) and over the promoted manganese oxide catalysts with alkaline metal and alkaline earth metal. Their properties and performance were characterized by using the Brunauer Emmett Teller (BET), temperature programmed reduction (TPR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The sequence of catalytic activity was as follows: Mn3O4>Mn2O3>MnO2, which was correlated with the oxygen mobility on the catalyst. Each addition of potassium (K), calcium (Ca) and magnesium (Mg) to Mn3O4 catalyst enhanced the catalytic activity of Mn3O4 catalyst. Accordingly, K, Ca and Mg seemed to act as promoters, and the promoting effect might be ascribed to the defect-oxide or a hydroxyl-like group. A mutual inhibitory effect was observed between benzene and toluene in the binary mixture. In addition, the order of catalytic activity with respect to VOC molecules for single compound is benzene>toluene, and the binary mixture showed the opposite order of toluene>benzene. © 2010.

Rhim J.-W.,Mokpo National University
Food Research International | Year: 2013

Multilayer films composed of PLA and agar/κ-carrageenan/clay (Cloisite® Na+) nanocomposite films were prepared, and the effect of lamination of PLA layers on the performance properties such as optical, mechanical, gas barrier, water resistance, and thermal stability properties was determined. The tensile strength (TS) of the agar/κ-carrageenan/clay nanocomposite films (67.8±2.1MPa) was greater than that of PLA films (43.3±3.6MPa), and the water vapor permeability (WVP), water uptake ratio (WUR), and water solubility (WS) of the nanocomposite films were higher than those of PLA films. The film properties of the multilayer films exhibited better properties of the component film layers. Especially, the WVP and water resistance of the bionanocomposite film were improved significantly, while the OTR of the PLA film decreased profoundly after lamination with PLA layers. Thermal stability of the bionanocomposite also increased after lamination with PLA layers. © 2013 Elsevier Ltd.

Kanmani P.,Mokpo National University | Rhim J.-W.,Mokpo National University
Food Hydrocolloids | Year: 2014

Antimicrobial bionanocomposite films were prepared with gelatin and silver nanoparticles (AgNPs) and organoclay (Cloisite 30B) and their film properties were characterized. Transparency of nanocomposite films decreased, but UV barrier was greatly improved, which was more pronounced with AgNPs-included films. Hydrophobicity and water vapor barrier properties were also improved after formation of nanocomposite. The incorporation of AgNPs or clay into the gelatin film could affect the mechanical properties of films. Tensile strength (TS) increased significantly in the gelatin/clay and gelatin/AgNPs/clay films while decreased in the elongation at break (EB). EDX and XRD analysis were performed to examine the presence of elemental silver and crystallinity of AgNPs in the films. Microscopic surface structure analysis showed homogenous compact surface structure of the composite films. Interaction between the polymer and nanoparticles was tested by FT-IR analysis. The nanocomposite films, especially for gelatin/AgNPs/clay, exhibited strong antibacterial activity against food borne pathogens. These results suggested that the use of gelatin based nanocomposite films will help to compete and eliminate the bacterial invaders and to improve the shelf life and quality of food. © 2013 Elsevier Ltd.

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