• Title/Summary/Keyword: adhesion amount

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Synthesis of O/W Emulsion of Alkyd Resin for Reducing of VOC (VOC 절감을 위한 알키드 수지의 O/W 에멀젼 제조)

  • Lee, Young Sang;Lee, Euy Soo;Ha, Jin Kuk
    • Journal of Adhesion and Interface
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    • v.11 no.1
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    • pp.9-14
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    • 2010
  • O/W emulsions were prepared with the phase inversion emulsification methods. The emulsifiers were used the UNIQ-1 (isopropylamine alkyl aryl sulphonate) and UNIQ-2 (alkoxylated glycol ether). Investigated effect that HLB value, agitator velocity and manufacture temperature get in mean particle size of emulsions. Mean particle size receives much effect of HLB value. Also, estimated stability about storage temperature and light. Emulsion's mean particle size was 193 nm lastly, reduced VOC amount used 90% than existing alkyd resin.

Enzymatic Conjugation of RGD Peptides on the Surface of Fibroin Microspheres

  • Jeon, Hyun Sang;Lee, Jin Sil;Hur, Won
    • Applied Chemistry for Engineering
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    • v.31 no.1
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    • pp.67-72
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    • 2020
  • Biomaterials are frequently functionalized with Arg-Gly-Asp (RGD) peptides to provide cell adhesion sites. In this study, RGD peptides were enzymatically coupled on to the surface of fibroin microspheres. Papain exhibited a strong preference for dansyl phenylalanine for the peptide formation with fibroin microspheres. Thus, RGD1 peptide was designed to carry cysteine to both sides of the sequence, glycine as a spacer and two residues of phenylalanine at the C-terminal (CRGDCGFF). The enzymatic modification facilitated by an increasing amount of substrate and by the presence of organic solvent, dimethylsulfoxide at 25% (v/v). Microspheres coupled with RGD1, showed a significantly different precipitation property and an increased apparent volume, possibly due to the steric hindrance of RGD peptides on the surface. Transmission electron microscopy also confirmed the presence of cysteine residues in RGD1 coupled on the surface of microspheres stained with gold nanoparticles. RGD1-microspheres significantly facilitated the growth of murine fibroblast 3T3 cells even under non-adhesion culture conditions.

Fermentation Characteristics and anti-Helicobacter pylori Activity of Aqueous Broccoli Fermented by Lactobacillus plantarum MG208

  • Yang, Ji-Won;Kim, Kyung Tack;Kim, Sung Soo
    • Journal of Applied Biological Chemistry
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    • v.58 no.1
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    • pp.89-95
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    • 2015
  • Helicobacter pylori infection causes gastrointestinal diseases such as chronic gastritis, peptic ulcers, and may lead to gastric cancer. Several studies have reported that lactobacilli present on broccoli show inhibitory activity against H. pylori. Here, we evaluated aqueous broccoli, fermented by Lactobacillus plantarum MG208, for its fermentation characteristics and anti-H. pylori activities including antibacterial activity, growth inhibition, anti-adhesion, and urease inhibition. The results indicated that the fermentation characteristics changed significantly depending on the amount of aqueous broccoli used for fermentation (p <0.05). There was no significant difference between the samples before fermentation (p >0.05). However, a significant concentration-dependent difference was noted in antibacterial activity and urease inhibition (p <0.05) following the addition of aqueous broccoli. Growth inhibition in the 10 mg/mL sample was significantly higher as compared to the negative control and similar to that with amoxicillin (positive control) (p <0.05). Anti-adhesion activity of aqueous broccoli was also significantly different (p <0.05) from the negative control. Therefore, aqueous broccoli fermented by L. plantarum MG208 could prove useful as a functional diet for protection of the gastric environment against H. pylori infection.

Effects of Co-doping on Densification of Gd-doped CeO2 Ceramics and Adhesion Characteristics on a Yttrium Stabilized Zirconia Substrate

  • Lee, Ho-Young;Kang, Bo-Kyung;Lee, Ho-Chang;Heo, Young-Woo;Kim, Jeong-Joo;Lee, Joon-Hyung
    • Journal of the Korean Ceramic Society
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    • v.55 no.6
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    • pp.576-580
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    • 2018
  • In this study, a small amount of CoO was added to commercial Gd-doped $CeO_2$ (GDC) powder. The CoO addition greatly enhanced sinterability at low temperatures, i.e., more than 98% of relative density was achieved at $1,000^{\circ}C$. When GDC/8YSZ (8 mol% yttrium stabilized zirconia) bilayers were sintered, Co-doped GDC showed excellent adhesion to the YSZ electrolyte. Transmission electron microscope (TEM) analysis showed that there were no traces of liquid films at the grain boundaries of GDC, whereas liquid films were observed in the Co-doped GDC sample. Because liquid films facilitate particle rearrangement and migration during sintering, mechanical stresses at the interface of a bilayer, which are developed based on different densification rates between the layers, might be reduced. In spite of $Co^{2+}$ doping in GDC, the electrical conductivity was not significantly changed, relative to GDC.

Application of Taguchi Method and Orthogonal Arrays for Optimization of Adhesion of $SrZrO_3$ Coatings on Ag/Bi(2223) Tapes

  • Lee, Se-Jong;Lee, Deuk-Yong;Song, Yo-Seung;Kim, Bae-Yeon
    • Progress in Superconductivity and Cryogenics
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    • v.5 no.1
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    • pp.13-16
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    • 2003
  • Adhesion of $SrZrO_3$ resistive oxide barrier on Ag sheathed Bi(2223) tapes prepared by the sol-gel and dip-coating method was evaluated with an aid of Taguchi method and Lie($2^1{\times}3^7$) orthogonal arrays to determine the optimal process combination of levels of factors that best satisfy the bigger is better quality characteristic (QC=B). For analyses of results statistical calculations such as average and analysis of variance (ANOVA) were employed to analyze the results for improving the performance qualities of the dip-coated $SrZrO_3$ film. Experimentally, the performance of the films was evaluated in terms of bond strength by varying Sr/Zr moi ratio (A), amount of organic vehicle additives (B), drying temperature (C) and time (D), heat treatment temperature (E) and time (F), respectively. The optimal combination of levels of factors was determined to be $A_3B_2C_3D_2E_1F_3$ having a 90% confidence level.

Formulation and Pharmaceutical Properties of Mucoadhesive Film Containing Dipotassium Glycyrrhizate (구내염증 치료용 구강점막 필름제의 제제설계와 약제학적 성질)

  • Rhee, Gye-Ju;Lee, Duk-Keun;Sin, Kwang-Hyun;Park, Chong-Bum
    • Journal of Pharmaceutical Investigation
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    • v.29 no.2
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    • pp.127-136
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    • 1999
  • In order to eliminate demerits of conventional dosage forms, dipotassium glycyrrhizate was formulated as a slim mucoadhesive film type dosage form. The mucoadhesive drug layer gel containing dipotassium glycyrrhizate was prepared using $Noveon^{\circledR}$ AA-1, hydroxypropylcellulose-M, ethylcellulose N 100 and citric acid, and the protective layer gel by using ethylcellulose N 100, $Eudragit^{\circledR}$ RS and castor oil. The viscosity of drug layer gel of mucoadhesive film was enhanced as the increased amount of $Noveon^{\circledR}$ AA-1 or hydroxypropyl cellulose-M. The drug content was unifonnly $1160{\pm}14.6\;{\mu}g$, and was varied within 3.5%. The optimum film dosage form showed a good fluidity and malleability of drug layer, with 179 g of thickness, pH 5.7, 411 min of in vitro adhesion time and 172 g in gravity adhesive strength. The release time of drug from the mucoadhesive film was significantly shorter but was delayed when polymers such as ethylcellulose was added. From these results, the new mucoadhesive film may be effective for the treatment of aphthous stomatitis.

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수성 고분자 - 탄소나노튜브 복합 분산 용액을 이용한 전계 방출 소자의 제작

  • Jeong, Hyeok;Kim, Do-Jin
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2011.05a
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    • pp.66.2-66.2
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    • 2011
  • A polymer-based multi-walled carbon nanotube (MWCNT) field emission device was fabricated from a composite dispersion of MWCNTs and waterborne polymethyl methacrylate (PMMA). The waterborne PMMA synthesized through the emulsion polymerization method was added to minimize the reagglomeration of dispersed MWCNTs with surfactants in water, and increase the adhesion between the and the substrate. The field emission properties of the fabricated device were optimized by adjusting the density of the emitter and the adhesion between the MWCNTs and the substrate. These were done by controlling the polymer concentration added to the MWCNT dispersion, as well as the amount of spray coating on the substrate. The results confirm the successful fabrication of a polymer-based MWCNT field emission device with a low field of 1.07 $V/{\mu}m$ and a good electric field enhancement factor of 2445. The device was fabricated by adding 0.8 mg/mL of polymer solution to the MWCNT dispersion and applying 20 cycles of spray coating. Application of this same MWCNT/polymer composite solution to a flexible polymer substrate also resulted in the successful fabrication of an electric field emission device with uniform emission and long time stability.

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Preparation of Wood Adhesives from the Rice Powder and pMDIs; Characterizations of Their Properties

  • Lee, Sang-Min;Joo, Ji-Hye;Lee, Hyang-Yeol
    • Journal of the Korean Applied Science and Technology
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    • v.32 no.4
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    • pp.607-615
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    • 2015
  • To investigate the adhesion effect of various kinds and contents of polymeric methylene diphenyl diisocyanates (pMDIs) on adhesion performance, wood adhesives (A-1~5) were synthesized and characterized. As results, when the amount of pMDI increased in adhesives, the dry tensile strength was found to be proportionally increased sustaining at around $16.0{\sim}21.6kgf/cm^2$. The polyurethane (PU) resin, which used M11S as a source of pMDI showed the best wet tensile strength at $11.9kgf/cm^2$ and cyclic boil tensile strength at $8.1kgf/cm^2$, which satisfied the requirement of over $7kgf/cm^2$. Thermal properties of the rice powder (RP) based polyurethane resins were characterized by differential scanning calorimetry (DSC) and Thermal gravimetric analysis (TGA). Thermal stability of polyurethane resins increased to $250^{\circ}C$ with adding pMDIs. The more pMDI (M5S) was added to adhesive, the higher thermal stability of the resin was observed by TGA.

Fabrication and characterization of block copolymer (PCL/PCL-PEG) nanofibers binding with collagen by electrospun (콜라겐 코팅된 블록공중합(PCL/PCL-PEG) 나노섬유의 제조 및 특성분석)

  • Lee, Jin Woo;Yoon, Kuk Ro
    • Analytical Science and Technology
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    • v.27 no.5
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    • pp.228-233
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    • 2014
  • Electrospun polymeric nanofibers have been extensively studied for biomedical materials because of their unique structures and relatively easy fabrication with biocompatible polymers. The amount of surface exposed amine groups increases as the blend ratio of block copolymer increases. Cell attachments on the nanofibers change according to the ratio of the block copolymer ((Poly(e-caprolactone, PCL), Poly(e-caprolactone)-Poly (ethylen glycol-$NH_2$)) in the blend. We assume that the PEG and amine moiety plays a significant role in biocompatibility of nanofiber surfaces. Collagen was used as a grafting material on the composite nanofibers to enhance the cell adhesion because the collagen is a major constituent of connective tissue.

Effect of PPG, MDI, 2-HEMA and butyl acrylate content on the properties of polyurethane adhesive (폴리우레탄 접착제의 물성에 미치는 PPG, MDI, 2-HEMA 및 butyl acrylate량의 영향)

  • Park, Chan Young
    • Elastomers and Composites
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    • v.49 no.3
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    • pp.245-252
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    • 2014
  • FT-IR measurement and the physical properties of polyurethane adhesive prepared from the polyol, isocyanate, 2-HEMA and other acrylate monomers were examined. The softening point, viscosity, adhesion strength and mechanical properties of the PU adhesives were reviewed by Ring and Ball method, Brookfield viscometer and universal test machine, respectively. Results revealed that increment of both PPG amount and butyl acrylate content decreased softening point, adhesion strength, tensile strength and 100% modulus. However as 2-HEMA and MDI content increased the mechanical properties including tensile strength, 100% modulus increased, and also the viscosity and NCO content increased.