• Title, Summary, Keyword: 가교화

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A study on the space charge in power cable by laser-induced pressure pulse method (Laser 유기 압력 Pulse법에 의한 전력 케이블중의 공간전하 분포에 관한 연구)

  • ;;;M.Mizutani
    • Electrical & Electronic Materials
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    • v.6 no.4
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    • pp.347-353
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    • 1993
  • 레이저 유기 압력 펄스법을 이용하여 가교폴리에틸렌필름과 전력케이블의 공간전하의 성질을 정량적으로 연구하여 다음과 같은 결론을 얻었다. 잔류가교제를 갖는 XLPE에서는 음극으로부터 현저한 전자주입이 나타나고 시료전체에 걸쳐 부의 공간 전하가 형성되었으며 음극으로 부터의 전자 주입은 전계상승에 따라 증가 하였다. XLPE 전력 케이블에서는 잔류가교제가 이온화하여 생긴 정 및 부의 헤테로 공간 전하가 음극 및 양극 부근에 형성되었다.

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Physical Properties of Poly(vinyl alcohol) with Polyamide-epichlorohydrin as a Wet Strength Additive for Paper (Polyamide-epichlorohydrin 지력 증강제 함유 폴리비닐알코올의 물성 연구)

  • Jang, Yunjae;Lee, Hwaljong;Kang, Ho-Jong
    • Polymer Korea
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    • v.37 no.6
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    • pp.730-735
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    • 2013
  • The physical properties of poly(vinyl alcohol) (PVA) with polyamide-epichlorohydrin (PAE) for wet strength additives in paper industry were investigated. Upon introducing PAE to PVA, not only melting and crystallization enthalpy in DSC but also the area of diffraction peaks in XRD decreased, which represented the fact that PAE acted as a crosslinking agent for PVA. However, this crosslinking seemed to be physical crosslinking having relatively less bonding energy compared to chemical crosslinking since the crystallization in PVA was able to take place by thermal annealing. This physical crosslinking and crystallization by thermal annealing enhanced the thermal stability and mechanical strength in PVA and consequently, these improvements are desired in the paper manufacturing process to increase the dry and wet strength in the paper.

Influence of Crosslinking on Gelatinization Behavior and Morphological Change of Potato Starch (가교결합 감자 전분의 호화특성과 형태학적 변화)

  • Kim, Hyang-Sook;Lee, Young-Eun
    • Korean Journal of Food Science and Technology
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    • v.28 no.3
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    • pp.580-586
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    • 1996
  • Gelatinization behavior and morphology of epichlorohydrin-crosslinked potato starches (XPs) were investigated. Native potato starch showed a very steep single stage swlling pattern, but crosslinked starches showed various patterns with the degree of crosslinking. Swelling power, solubility and light transmittance were reduced drastically as the degree of crosslinking increased. Brabender initial pasting temperature and peak temperature of crosslinked starches increased because the crosslinking reinforces the intermolecular net work of the starches. Although the swelling of the potato starch granule was inhibited by crosslinking as compared to that of the native one, Brabender peak viscosities (6.5% w/v, db) were on the order of 2,500 units for the native potato starch, 3,700 for the XP with 2.300 anhydroglucose units per crosslinking (AGU/CL) and 3,400 for the XP with 2,100 AGU/CL, due to the decreased breakdown of the swollen granule resulting from the resistance to heat and shear. The XP with 1,900 AGU/CL, however, did not show the peak viscosity and the viscosity was on the order of 500 units because of the excessive unhibition of the swelling. Unlike the native potato starch, 6.5%(m/v, db) pastes of the crosslinked potato starches could form gels, which could be predicted from the Brabender setback and consistency index. When the degree of crosslinking is low, random contraction and radial swelling of the granule was possible. As the degree of crosslinking increased, morphological change became similar to the single dimensional tangential swelling observed from the lenticular wheat starch. These morphological change during heating in excess water explained the gelatinization behaviors of crosslinked starches tested.

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Characteristics of PVA for pervaporation membrane (투과증발막용 PVA 제조특성)

  • Gang, So-Ra;Yoon, Suk-Young;Chang, Duk-Rye
    • 한국신재생에너지학회:학술대회논문집
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    • pp.518-519
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    • 2009
  • 투과증발은 저 에너지 분리기술로서 공비혼합물의 분리 및 유기화화물을 선택적으로 분리하는 공정에 활용되고 있다. 투과증발공정을 위한 막으로 쓰이는 대표적인 고분자 재료인 친수성 고분자 PVA(Poly(vinyl alcohol)는 하이드로실 그룹을 포함하고 있어 물에 대한 선택도가 뛰어난 장점을 가지고 있다. 그러나 PVA는 물에 대한 친화력이 높아 투과증발막으로 적용하기 위해서는 내수성을 향상시키기 위하여 가교시킨후 투과증발막으로 사용가능하다. 본 연구에서는 PVA 분리막을 투과증발막으로 적용하기 위하여 PVA를 전기방사에 의해 나노섬유로 제조하고 제조된 나노섬유가 수용액에서 내수성을 갖게 하기 위해 10-70%의 KOH수용액에 가교화 하여 특성을 알아보았다.

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Development of Crosslinked Sulfonated Poly(ether sulfone)s as Novel Polymer Electrolyte Membranes (새로운 연료전지용 술폰화된 PES계 가교 고분자 전해질 막의 개발)

  • Oh, Young-Seok;Lee, Myung-Gun;Kim, Tae-Hyun
    • Journal of the Korean Chemical Society
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    • v.53 no.3
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    • pp.345-354
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    • 2009
  • Sulfonated poly(ether sulfone)s (PESs) with a network structure were prepared by heat-induced crosslinking of the allyl-terminated telechelic sulfone polymers using a bisazide and their structure was analyzed by $^1H$ NMR. Having both uniform distribution of the hydrophilic conductive sites and controlled hydrophobic nature by minimized crosslinking, the crosslinked polymer (PES-60) membrane offered excellent proton conductivity at high temperature with a good thermal stability. In addition, selectivity of the crosslinked membrane (PES-60) was more than three times than that of Nafion$^{(R)}$.

A Study on the Reactivity of Dioxygen Bridged Palladium Complexes Having Amine Ligands (아민을 리간드로 갖는 산소가교 팔라듐 착화합물의 반응성에 관한 연구)

  • Chung, Pyung-Jin
    • Applied Chemistry for Engineering
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    • v.3 no.3
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    • pp.471-481
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    • 1992
  • This study is related to the reactivity of dioxygen bridged palladium complexes having amine ligands. New dloxygen bridged palladium complexes were prepared using superoxide ion(${O_2}^-$) as an oxygen source. The reactions of dioxygen palladium complexes prepared in the study were examined in order to clarify the nature of the coordinated dioxygen. Treatments of a solution of the dioxygen bridged palladium complexes in benzene by water, methanol, acetic acid gave hydrogen peroxide($H_2O_2$) and hydroxy, methoxy, acetoxy-bridged palladium complexes, respectively. The dioxygen bridged palladium complexes reacted with substitution phenols of salicylaldehyde, 8-hydroxyquinoline and active mothylenes of acetylacetone, dimethyl malonate to afford mononuclear complexes of palladium and hydrogen peroxide. Furthermore, she dioxygen bridged palladium complexes changed to acetonyl bridged palladium complex and hydrogen peroxide reacting with acetone. The results suggest that dioxygen is coordinated as peroxo (${O_2}^{2-}$) in the complexes and behaves as a strong base.

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A Study on the Electron Beam Crosslinking of Acrylic Pressure Sensitive Adhesives for Polarizer Film (전자선 조사를 통한 편광필름용 아크릴계 고분자의 가교화 반응에 대한 연구)

  • Park, Jung-Jin;Choi, Hong-June;Ko, Hwan-Soon;Jeong, Eun-Hwan;Youk, Ji-Ho
    • Polymer Korea
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    • v.36 no.3
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    • pp.344-350
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    • 2012
  • New pressure sensitive adhesives (PSAs) for polarizer film were prepared by electron beam (e-beam) radiation to acrylic copolymers, and their adhesive properties were investigated. The acrylic copolymers were synthesized by free radical polymerization of $n$-butylacrylate (BA), 2-hydroxyethyl methacrylate (HEMA), and acrylic acid (AA). The acrylic copolymers were coated on PET release films to a thickness of 25 ${\mu}m$, laminated to polarizer films, and then radiated with e-beam at room temperature. Gel fractions of all the acrylic copolymers after e-beam radiation at 50 kGy were higher than 93%, and their crosslinking densities were increased with increasing the content of HEMA units. PSA prepared by e-beam radiation of acrylic copolymer synthesized with a feed ratio of BA/HEMA/AA = 89.5/10/0.5 (w/w/w) at a dose of 50 kGy exhibited the best adhesion performances in terms of peel strength, creep resistance, durability and reliability, and light leakage. It is expected that the preparation method of PSAs via e-beam irradiation will improve the producibility and workability of polarizer film for liquid crystal display.

The Effect of Crosslinking on the Actuation of Electroactive IPMC Prepared with Fluoroalkyl Methacrylate/Acrylic Acid/HEMA Copolymer (Fluoroalkyl Methacrylate/Acrylic Acid/2-HEMA 공중합체로 제조한 IPMC의 구동 특성에 미치는 가교의 영향)

  • Jeong, Han-Mo;La, Young-Soo
    • Polymer Korea
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    • v.29 no.5
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    • pp.463-467
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    • 2005
  • In order to enhance the actuation force of ionic polymer-metal composite (IPMC) made with the acrylic copolymer of fluoroalkyl methacryate, acrylic acie, and 2-hydroxyethyl methacrylate(HEMA), the hydroxy group of HEMA was corsslinked with 1,3-diethoxy-1,1,3,3-tetramethyldisiloxane. The water uptake was reduced and the mechanical strengths and the actuation force of the membrane was improved by crosslinking. However, current and deformation responses of IPMC were decreased by crosslinking.