• Title/Summary/Keyword: Cross linking

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Physicochemical Properties of Cross-linked and Partially Enzymatically Hydrolyzed (CLE) Waxy Rice Starch (가교화 후 효소처리(CLE) 찹쌀 전분의 물리화학적 특성)

  • Yu, Chul;Kim, Sung-Woo;Kim, Chong-Tai;Choi, Sung-Won;Kim, Byung-Yong;Baik, Moo-Yeol
    • Korean Journal of Food Science and Technology
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    • v.40 no.3
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    • pp.290-296
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    • 2008
  • This study examined the physicochemical properties of chemically and enzymatically cross-modified waxy rice starches. The waxy rice starch was cross-linked using phosphorous oxychloride, and then partially hydrolyzed with four commercial ${\alpha}$-amylases (Fungamyl, Termamyl, Liquozyme, Kleistase). Swelling power and the moisture sorption isotherm did not change with cross-modification. Two cross-modified waxy rice starches (hydrolyzed with Termamyl and Liquozyme) showed higher solubilities than native starch and the two other cross-modified starches (hydrolyzed with Fungamyl and Kleistase). In terms of RVA characteristics, the two cross-modified waxy rice starches hydrolyzed with Termamyl and Liquozyme, respectively, had lower peak viscosity, holding strength, and final viscosity than the native starch. However, the two starches hydrolyzed with Fungamyl and Kleistase, respectively, revealed higher peak viscosity, holding strength, and final viscosity than the native starch. No differences were displayed in the X-ray diffraction patterns and DSC thermal characteristics of the cross-modified waxy rice starch as compared to both the native and cross-linked starches, indicating that cross-linking and enzymatic hydrolysis occurred in the amorphous region and did not alter the crystalline region.

Photopolymerization of Methyl methacrylate with Phenylsilane

  • 홍란영;우희권;함희숙
    • Bulletin of the Korean Chemical Society
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    • v.16 no.4
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    • pp.360-363
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    • 1995
  • The photopolymerization of methyl methacrylate(MMA) with phenylsilane wasperformed. The molecular weights of the poly(MMA) containing SiH moieties were increased with augment of molar ratio of PhSiH3 over MMA by cross-linking via hydrosilation at the expense of isolated yield. Phenylsilane apparently influenced on the photopolymerization as a chain transfer agent and solvent.

Electrochemical and Mechanical Characteristics of Covalently Cross-Linked SPEEK Polymer Electrolyte Membrane for Water Electrolysis (수전해용 공유가교 SPEEK 고분자 전해질 막의 전기 화학적 및 기계적 특성)

  • Kim, Kyung-Eon;Jang, In-Young;Kweon, Oh-Hwan;Hwang, Yong-Koo;Moon, Sang-Bong;Kang, An-Soo
    • Transactions of the Korean hydrogen and new energy society
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    • v.18 no.4
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    • pp.391-398
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    • 2007
  • The covalently cross-linked sulfonated polyetheretherketone (CL-SPEEK) membrane was prepared by four-step synthesis of sulfonation-sulfochlorination, partial reduction, lithiation, and cross-linking, and its electrochemical and mechanical properties were investigated for water electrolysis application. The prepared ion exchange membranes showed good electrochemical and mechanical properties; proton conductivity of 0.116 S/cm at $80^{\circ}C$, water uptake of 44.6%, ion exchange capacity of 1.75 meq/g-dry-memb., tensile strength of 64.25 MPa and elongation of 61.11%. The membrane electrode assembly (MEA) with homemade membranes were prepared by non-equilibrium impregnation-reduction (I-R) method. Especially, the electrochemical surface area (ESA) and roughness factor of CL-SPEEK electrolyte by cyclic voltammetry method were 23.46 $m^2/g$ and 307.3 $cm^2-Pt/cm^2$, respectively. The prepared MEA was used in the unit cell of water electrolysis and the cell voltage was 1.81 V at 1 A/$cm^2$ and $80^{\circ}C$, with platinum loadings of 1.31 mg/$cm^2$.

Effects of cross-linking methods for polyethylene-based carbon fibers: review

  • Kim, Kwan-Woo;Lee, Hye-Min;An, Jeong-Hun;Kim, Byoung-Suhk;Min, Byung-Gak;Kang, Shin-Jae;An, Kay-Hyeok;Kim, Byung-Joo
    • Carbon letters
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    • v.16 no.3
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    • pp.147-170
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    • 2015
  • In recent decades, there has been an increasing interest in the use of carbon fiber reinforced plastic (CFRP) in aerospace, renewable energy and other industries, due to its low weight and relatively good mechanical properties compared with traditional metals. However, due to the high cost of petroleum-based precursors and their associated processing costs, CF remains a specialty product and as such has been limited to use in high-end aerospace, sporting goods, automotive, and specialist industrial applications. The high cost of CF is a problem in various applications and the use of CFRP has been impeded by the high cost of CF in various applications. This paper presents an overview of research related to the fabrication of low cost CF using polyethylene (PE) control technology, and identifies areas requiring additional research and development. It critically reviews the results of cross-linked PE control technology studies, and the development of promising control technologies, including acid, peroxide, radiation and silane cross-linking methods.

Tuning the Stiffness of Dermal Fibroblast-encapsulating Collagen Gel by Sequential Cross-linking (연속가교를 통한 피부 진피세포 담지 콜라겐 겔의 강도 제어)

  • Jung, Mun-Hee;Shin, Sung Gyu;Lim, Jun Woo;Han, Sa Ra;Kim, Hee-Jin;Jeong, Jae Hyun
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.44 no.1
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    • pp.23-29
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    • 2018
  • In this study, sequential cross-linked collagen gels were successfully prepared with collagen, which is biomaterial, and acrylamide (AAm), which is a synthetic monomer. The elastic moduli (E) of cross-linked collagen gels were increased from 1.5 to 3.0 kPa by varying of AAm concentrations. In addition, human dermal fibroblasts were encapsulated into the porous pores introduced into the gels, and cell growth and behavior were investigated. Increasing E of the gels led to decreases in cell growth rate, while the cellular glycosaminoglycan (GAG) production level was elevated. Overall, the growth and cellular activity of skin cells were influenced by the extracellular matrix properties of the collagen gels. In conclusion, these results will be highly useful for designing reconstructive skins and various tissue engineering researches.