• Title/Summary/Keyword: 가교결합

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Effect of Degree of Interfacial Interlinking on Adhesive Strength and Fracture Morphology of Rubber Layers (고무층간 가교정도가 접착강도 및 파괴형태에 미치는 영향)

  • Kim, Hyeon-Jae;Kaang, Shin-Young;Nah, Chang-Woon
    • Elastomers and Composites
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    • v.34 no.1
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    • pp.31-44
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    • 1999
  • Interfacial adhesive strength between the fully-crosslinked and partially-crosslinked rubber layers were Investigated at the temperature range of $30{\sim}120^{\circ}C$ for four different rubbers(NR, SBR, EPDM, BIMS). The surfaces of interfacial failure were also investigated using a scanning electron microscopy(SEM). The physical interlinking played a major role in the adhesive strength between the fully-crosslinked rubber layers. When a partially-crosslinked rubber layer was bonded to the fully-crosslinked one, the chemical as well as the physical interlinking affected the adhesive strength. NR showed a "interfacial knotty tearing" pattern, while EPDM showed a typical "cross-hatched" one when the adhesive strength approached to the cohesive tear strength of each material.

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A Study on the Physical Properties of a Compound Using the Crosslinking of Vinylized-mesoporous Silica and Regenerated Polyethylene (비닐화 실란이 도입된 메조포러스 실리카와 재생 폴리에틸렌의 가교결합을 이용한 컴파운드의 물성 연구)

  • Tae-Yoon Kim;Hyun-Ho Park;Chang-Seop Lee
    • Journal of the Korean Chemical Society
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    • v.67 no.6
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    • pp.420-428
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    • 2023
  • Crosslinking was introduced into vinylized-mesoporous silica and recycled polyethylene. By introducing a vinyl group into the mesoporous silica, it becomes a material capable of inducing cross-linking with non-polar polyethylene. By synthesizing vinylized-mesoporous silica and inducing crosslinking with recycled polyethylene, a recycled polyethylene composite with improved physical properties than existing recycled polyethylene was synthesized. In addition, even when a small amount is added according to the grade of recycled polyethylene using vinylized-mesoporous silica, the crosslinking reaction proceeds and all physical properties are improved. Four types of vinylized-mesoporous silica were synthesized, and the shape, microstructure, and functional groups were analyzed by TEM, BET, FT-IR, and XRD. Using vinylized-mesoporous silica, three types of compounds were blended by crosslinking reaction with recycled polyethylene. In order to confirm the presence or absence of crosslinking, analysis was performed using XPS and FT-IR, and physical properties such as tensile strength, elongation, flexural strength, and flexural modulus were confirmed using a universal testing machine. As a result, by applying vinylized-mesoporous silica to recycled polyethylene in various grades, the weak physical properties of existing recycled polyethylene were overcome. By applying the vinylized-mesoporous silica, recycled polyethylene composite material that overcomes the weak physical properties to the normal polyethylene, it shows the optimal physical property index that can be used commercially. Therefore, it is expected that it can potentially increase the use of recycled polyethylene and recycle resources.

Vapor Permeation Separation of MTBE-Methanol Mixtures Using Cross-linked PVA Membranes (가교된 PVA 막을 이용한 MTBE/methanol 혼합물의 증기투과(Vapor Permeation)분리)

  • 김연국;임지원
    • Membrane Journal
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    • v.10 no.3
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    • pp.148-154
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    • 2000
  • Poly(vinyl alcohol)(PVA)/sulfur-siccinic acid(SSA) membrane performances have been studied for the vapor permeation separation of methyl tort-butyl ether(MTBE)/methanol mixtures with varying operation temperatures, amount of cross-linking agents, and feed compositions. 1'here are two factors, the membrane network and the hydrogen bonding, in the swelling measurements of PVA/SSA membranes. These two factors act interdependently on the membrane swelling. The sulfuric acid group in SSA took an important role in the membrane performance. The cross-linking effect might be more dominant than the hydrogen bonding effect due to the sulfuric acid group at 7% SSA membrane. Hydrogen bonding effect was more important for 5% SSA membrane. In vapor permeation, density or concentration of methanol in vapor feed is lower than that of methanol in liquid feed, as a result, the hydrogen bonding portion between the solvent and the hydroxyl group in PVA is reduced in vapor permeation. In this case, the 7% SSA membrane shows the highest separation factor of 2187 with the flux of 4.84g/$m^2$hr for MTBE/methanol=80/20 mixtures at 3$0^{\circ}C$.

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Effects of Cross-linked RS 4 starches on Pasting Profiles of Wheat Starch using RVA (밀전분의 RVA 호화특성에 가교결합 RS 4 저항전분의 첨가가 미치는 영향)

  • Shin, Mal-Shick;Mun, Sae-Hun;Woo, Kyung-Soo
    • Korean Journal of Food Science and Technology
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    • v.33 no.1
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    • pp.157-160
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    • 2001
  • RS yields and swelling powers of cross-linked RS 4 starches and effects of RS 4 starches on the pasting profiles of RS 4 added wheat starch were measured using RVA. RS yields by AOAC method were different among RS 4 starches and RS levels were higher in low swelling RS 4 starches than moderate swelling RS 4 starches. Swelling power was different with botanical source of starch and preparing procedure of RS 4 starches. The pasting curves of RS 4 added wheat starches showed increasing initial pasting temperature and lower viscosity but the patterns were similar to those of wheat starch. The pasting viscosity pattern of RS 4 added wheat starches was related with swelling power of RS 4 starch.

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Thermo-reversible Crosslinking Elastomer through Supramolecular Networks (초분자 네트워크를 이용한 열가역성 가교 탄성체)

  • Bae, Jong-Woo;Oh, Sang-Taek;Kim, Gu-Ni;Baik, Hyen-Jong;Kim, Won-Ho;Choi, Sung-Seen
    • Elastomers and Composites
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    • v.45 no.3
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    • pp.165-169
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    • 2010
  • Recently supramolecular network thermo-reversible crosslinking elastomer having flexibility, various functionality, and advantages of thermoplastic elastomer (TPE) such as recycle and easy processbility is introduced. Although thermo-reversible bonds such as hydrogen bond and ionic cluster is recognized as a common technology since 1990, control technology of bonding and dissociation of crosslink in supramolecular network is a recent technology. In this review, characteristics of thermo-reversible crosslinking elastomer having rheological properties of TPE and reinforcing behaviors of thermoset elastomer are summarized.

The Study on Organic Hardners for Gelatin of Photographic Emulsion (사진유제용 Gelatin의 유기경화제에 관한 연구 (I))

  • 청진쑹
    • Journal of the Korean Graphic Arts Communication Society
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    • v.1 no.1
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    • pp.69-75
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    • 1983
  • Among the gelatin hardness for photographic emulsion, the formal dehyde , dialdehydes, n-Methylol compounds, ketonea, carbonylic acid and carbamic acid derivatives, and s-Triazine derivatives were studied. The greater purts of hardeners formed cross-link by the reaction with ${\varepsilon}$-Amino group in the lysine and OH group in the hydroxylysine. Glutaraldehyde produced most stable cross-link due to the formation of pyridinum ion. 2.5 hexanedione and 3-hexone-2.5-dione possible to use as the ketone hardner . The sodium salt of 2.4-dichloro-6-hydroxy-S-Triazine was newly developed as the olefinic hardners for emulsion.lsion.

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BTCA/DMDHEU에 의한 면직물의 DP가공

  • 이주현;이의소
    • Proceedings of the Korean Fiber Society Conference
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    • 1998.10a
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    • pp.133-136
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    • 1998
  • DP가공은 면직물을 구성하고 있는 셀룰로오스 분자사이에 가교결합을 형성시켜 그 탄성한계를 높임으로써 구김을 방지할 목적으로 행해지는 가공이다. 현재 공업적으로 가장 많이 사용하고 있는 가교제는 셀룰로오스의 히드록시기와 ether형 가교를 형성하는 DMDHEU(dimethyloldihydroxyethylene urea) [1]이며 이와같은 ether형 가교제는 내가수 분해성이 높고 여러번의 세탁에도 견딜 수 있는 우수한 내구성을 지니고 있는 장점이 있으나 인체에 유해한 포름알데히드가 발생되는 단점이 있다. (중략)

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Hair Strengthening Effect of Silane Coupling and Carbodiimide Chemistry (카르보디이미드 반응과 실란 커플링을 이용한 모발강화 효과)

  • Son, Seong Kil;Choi, Wonkyung;Lim, Byung Tack;Song, Sang-hun;Kang, Nae Kyu
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.44 no.2
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    • pp.133-139
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    • 2018
  • Chemically damaged hair is vulnerable to external stimuli in daily life due to the weakened physical properties of the hair strand itself. The purpose of this work was to determine whether chemical conjugation between hair keratin proteins restores tensile strength and thus results inpreventing further deterioration under repeated combing. A model damaged hair tress was produced by a typical perm-process. Then, it was internally crosslinked by the bifunctional crosslinker (3-aminopropyl)triethoxysilane (APTES), via both silane coupling and carbodiimide chemistry. Physical properties, including tensile strength, Young's modulus, and plateau stress, were measured to verify the effect of internal crosslinking, and the existence of crosslinking was verified by Fourier transform infrared (FT-IR) spectroscopy. The degrees of hair breakage and split ends were evaluated by repeated combing-drying tests. Physical properties of chemically damaged hair were restored by internal crosslinking. Successful crosslinking of APTES via both silane coupling and carbodiimide chemistry was verified by FT-IR spectra. Prevention of breakage and split ends after repeated combing with heat was observed. Human hair can be weakened by chemical damage including perm-processing, so restoring such properties is a major issue in the hair care industry. This work shows that internal crosslinking of damaged hair via chemical conjugation would be a potent method to restore the healthy hair.