Effects of retention aids on the strength properties of paper

Won, Jong Myoung,Chun, Chul,OH, Joung Soo 圓光大學校 基礎自然科學硏究所 1984 基礎科學硏究誌 Vol.3 No.1

本 硏究는 抄紙時 가장 一般的으로 使用되고 있는 保留向上劑가 종이의 强度的 性質에 미치는 影響을 調査하기 위하여 alum과 cationic polyacrylamide를 40˚SR로 고해된 펄프슬러리에 여러 水準으로 加해 各條件別 效果를 測定하였다. 保留向上劑로 alum이 使用되었을 경우 裂斷長은 alum이 2% 添加될 때까지 계속 改善되었으나, 添加量이 점차 增加함에 따라 急速한 減少로 나타내었다. 그러나 非引裂度와 耐折度는 alum이 添加됨에 따라 無處理보다 낮은 數値를 나타내었으며, alum이 3% 添加되었을 때 다시 改善되었고, 그 以後는 다시 減少하는 傾向을 나타내었다. 한편 非破裂度는 alum이 添加됨에 따라 계속 減少하다가 5% 以上의 alum이 添加되었을 때 改善되어 다른 强度的 性質과는 다른 結果를 나타내었다. cationic polyacrylamide의 添加는 一般的으로 종이의 强度的 性質을 매우 改善시켰으나, 非引裂度는 오히려 惡化시키는 結果를 나타내었다. 이상과 같은 結果를 종합해 볼 때 保留向上劑에 依한 종이의 强度的 性質 改善은 用途 및 필요에 따라 적정수준의 量을 添加하므로써 얻어질 수 있음을 알 수 있다. This study was carried out to investigate the effects of retention aids on the strength properties of paper. The strength properties depend upon a kind of retention acid, the amount of addition. Generally, the addition of cationic polyacrylamide, except for tear factor, increased the strength properties. The addition of alum decreased the burst factor and folding endurance, the breaking length and tear factor improve at the optimum addition of alum. Therefore, it is need to select the addition amount of retention aid dependent on the uses and the need of strength properties.

Effects on Photocatalytic Degradation and Hydrogen Evolution of TiO₂ Coated CaLa₂(MoO₄)₄ and CaLa₂(MoO₄)₄:Er/Yb Nano Core-Shells and their Upconversion Photoluminescence

Oh, Won-Chun,Ye, She,Park, Jung Gyu,Lim, Chang Sung Chemic Publishing Company 2016 Asian Journal of Chemistry Vol.28 No.5

Anti-inflammatory effect of sugar-amino acid Maillard reaction products on intestinal inflammation model <i>in vitro</i> and <i>in vivo</i>

Oh, Jun-Gu,Chun, Su-Hyun,Kim, Da Hyun,Kim, Jin Hye,Shin, Hye Soo,Cho, Yong Soo,Kim, Yong Ki,Choi, Hee-don,Lee, Kwang-Won Elsevier 2017 Carbohydrate research Vol.449 No.-

<P><B>Abstract</B></P> <P>The Maillard reaction is a nonenzymatic reaction between an amino acid and a reducing sugar that usually occurs upon heating. This reaction occurs routinely in cooking, generates numerous products, which are collectively referred to as Maillard reaction products (MRPs) contributing to aroma and color features. Advanced glycation end-products (AGEs) transformed from MRPs are participated in many types of inflammation reaction. In this study, various sugar-amino acid MRPs were prepared from three different amino acids (lysine, arginine, and glycine) and sugars (glucose, fructose, and galactose) for 1 h with heating at 121 °C. Treatment of lipopolysaccharide-stimulated RAW264.7 macrophages with the MRPs decreased nitric oxide (NO) expression compared to control without MRPs treatment. MRPs derived from lysine and galactose (Lys-Gal MRPs) significantly inhibited NO expression. The retentate fraction of Lys-Gal MRPs with cut-off of molecular weight of 3–10 kDa (LGCM) suppressed NO expression more effectively than did Lys-Gal MRPs. The anti-inflammatory effect of LGCM was evaluated using a co-culture system consisting of Caco-2 (apical side) and RAW264.7 or THP-1 (basolateral side) cells to investigate the gut inflammation reaction by stimulated macrophage cells. In this system, LGCM prevented a decreased transepithelial electrical resistance, and decreased both tumor necrosis factor-α production in macrophages and interleukin (IL)-8 and IL-1β mRNA expression in Caco-2 cells. In co-culture and <I>in vivo</I> dextran sulfate sodium (DSS)-induced colitis model study, we also observed the anti-inflammatory activity of LGCM.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Lysine-galactose conjugate is produced by autoclaving at 121 °C for 1 h. </LI> <LI> Cut-off of lysine-galactose is obtained fraction of 3–10 kDa by ultrafiltration. </LI> <LI> Fraction provides anti-inflammatory effect in co-culture system. </LI> <LI> Tumor necrosis factor-α in macrophage is decreased with fraction treated group. </LI> <LI> Fraction decreases IL-8 and IL-1β mRNA expression in intestinal cells. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Properties and Photocatalytic Activity of Pitch-binded ACF/TiO₂Composites

Oh, Won-Chun,Jung, Ah-Reum The Korean Ceramic Society 2008 한국세라믹학회지 Vol.45 No.3

Pitch-binded activated carbon fiber(ACF)/$TiO_2$ composite photocatalysts were prepared by Carbon Tetra Chloride (CTC) solvent mixing method with different mixing ratios of anatase to ACF. The result of the textural surface properties demonstrated that there is a slight increase in the Brunauer, Emmett and Teller (BET) surface area of composites with an increase of the amount of ACF. The surfaces structure morphologies of the composites were observed using an Scanning Electron Microscope (SEM). In the XRD patterns for all ACF/$TiO_2$ composites, the diffraction peaks showed the formation of anatase crystallites. The EDX spectra showed the presence of C, O and Si with strong Ti peaks. Most of these samples were richer in carbon and major Ti metal than any other elements. From the photo-decomposition results, the excellent activity of the ACF/$TiO_2$ composites between c/$c_0$ for methylene blue and UV irradiation time could be attributed to both the effects of the photocatalysis of the supported $TiO_2$ and adsorptivity of activated carbon fiber and another carbon derived from pitch.

Surface Properties of HCl Modified Ag-ACFs

Won-Chun Oh,Young-Shin Ko 한국탄소학회 2005 Carbon Letters Vol.6 No.4

Silver impregnated activated carbon fibers were post-modified using hydrochloric acid. Adsorption behaviors, SEM morphologies, and functional groups for the silver impregnated ACFs were compared with those of post-modified ACFs. Adsorption isotherms were used to characterize SBET, the pore structure and volume of silver-activated carbon fibers (ACFs) before and after acid post-treatment. In order to the reveal the causes of the differences surface states after the samples were washed with hydrochloric acid, outer surface and pore structure were investigated by SEM. And the type and quality of various functional groups were studied from FT-IR spectra and Boehm titration method. Finally, the quantitative properties in silver contents were also examined by EDX spectra.

Photocatalytic Oxidation for Organic Dye using Phenol Resin-based Carbon-titania Composites

Oh, Won-Chun,Na, Yu-Ri The Korean Ceramic Society 2008 한국세라믹학회지 Vol.45 No.1

Carbon/$TiO_2$ composite photocatalysts were thermally synthesized with different mixing ratios of anatase to phenol resin through an ethanol solvent dissolving method. The XRD patterns revealed that only anatase phase can be identified for Carbon/$TiO_2$ composites. The diffraction peaks of carbon were not observed, however, due to the low carbon content on the $TiO_2$ surfaces and the low crystallinity of amorphous carbon. The results of chemical elemental analyses of the Carbon/$TiO_2$ composites showed that most of the spectra for these samples gave stronger peaks for carbon and Ti metal than that of any other elements. The BET surface area increases to the maximum value of $488\;m^2/g$ with the area depending on the amount of phenol resin. From the SEM images, small $TiO_2$ particles were homogeneously distributed to a composite cluster with the porosity of phenol resin-based carbon. From the photocatalytic results, the MB degradation should be attributed to the three kinds of synergetic effects, such as photocatalysis, adsorptivity, and electron transfer by light absorption between supporter $TiO_2$ and carbon.

Surface Transition by Solvent Washing Effects and Biological Properties of Metal Treated Activated Carbons

Oh, Won-Chun Korean Chemical Society 2004 Bulletin of the Korean Chemical Society Vol.25 No.5

Metal treated activated carbons are prepared using various metals. Adsorption behaviors, morphologies, as well as antibacterial effects of metal treated samples are compared before and after solvent washing. Adsorption isotherms are used to characterize the porous structure of metal treated activated carbons before and after the solvent washing with acetone or ethyl alcohol. From these data, it is noticed that the changes in physicochemical properties of metal treated activated carbons depend on the solvents employed. Similar results are observed from BET data obtained from nitrogen adsorption isotherms. From scanning electron microscopy (SEM) studies, the changes in shape and size of metal particles are observed after the samples are washed with solvents. These changes result in different blocking effects, which, in turn, affect the adsorption behavior of metal treated activated carbons. X-ray diffraction (XRD) patterns of the samples treated with different metals are different each other. High intense sharp peaks attributed to metals are observed from silver treated samples, while the peaks are not observed from copper treated samples. To compare thermodynamic behavior of metal treated activated carbons washed with different type of solvents, differential scanning calorimetric (DSC) analysis is carried out. The analysis shows similar endothermic curves for all of the samples. Finally, antibacterial effects of metal treated activated carbon against Escherichia coli are discussed. Comparing the effects among the metals employed, highest effects are obtained from Cd, while lowest effects are obtained from Cu. Antibacterial activity becomes higher with the increase of the amount of metals treated, Optimum concentrations of metals to treat activated carbons, obtained from a shake flask test, are known to be 0.4, 0.1, and 0.6 moles for Ag, Cd, and Cu, respectively.

Silver Loading Effect for the Activated Carbon Fibers Pre-treated with Acid

Won-Chun Oh*,Min-Hyung Yum 대한화학회 2004 Bulletin of the Korean Chemical Society Vol.25 No.8

Surface Transition by Solvent Washing Effects and Biological Properties of Metal Treated Activated Carbons

Won-Chun Oh* 대한화학회 2004 Bulletin of the Korean Chemical Society Vol.25 No.5

Deintercalation and Thermal Stability of Na-graphite Intercalation Compounds

Won-Chun Oh 한국탄소학회 2001 Carbon Letters Vol.2 No.1

Na alloyed graphite intercalation compounds with stage 1 and 2 were synthesized using the high temperature and pressure technique. Thermal stability and staging transitions of the compounds were investigated depending on heating rates. The thermal stability and temperature dependence of the deintercalation compounds were characterized using differential scanning calorimeter (DSC) analyzer. Enthalpy of formations were confirmed at temperatures between 25 and 500℃, depending on the various heating rates. The structure ions and interlayer spaces of the graphite were identified by X-ray diffraction (XRD). Diffractograms of stages with non-integral (00l) values were obtained in the thermal decomposition process, and stacking disorder defects and random stage modes were observed. The average value of the interlayer C-C bond lengths were found approximately 2.12a and 1.23a from the diffractions. Based on the stage transition, the degree of the deintercalaton has a inverse-linear relationship against the heating rate.