• Title/Summary/Keyword: Photo crosslink

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Photostabilization and Cure Kinetics of UV-Curable Optical Resins Containing Photostabilizers

  • Cho, Jung-Dae;Kim, Sung-Hwa;Chang, In-Cheol;Kim, Kwon-Seok;Hong, Jin-Who
    • Macromolecular Research
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    • v.15 no.6
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    • pp.560-564
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    • 2007
  • The photostabilization and cure kinetics of UV-curable, optical resins containing various formulations of photostabilizers were investigated to determine the system with the highest cure conversion and durability. Photo-DSC analysis revealed that increasing the concentration of a UV absorber (UVA) decreased both the crosslink density and the cure rate due to competition for the incident photons between the photoinitiator and the UVA, whereas including a hindered amine light stabilizer (HALS) hardly affected either the cure conversion or the cure rate due to its very low absorption of 365 nm. This result was confirmed by FTIR-ATR spectroscopy and UV-visible spectroscopy analyses. QUV ageing experiments showed that the cure conversion and durability were the highest for the UVA/HALS formulation at a ratio of 1 : 2, which is due to their synergistic action.

Filler-Elastomer Interactions. 10. Ozone Treatment on Interfacial Adhesion of Carbon Blacks/NBR Compounds (충전재-탄성체 상호작용. 10. 카본블랙/NBR 복합재료의 계면 접착에 미치는 오존처리의 영향)

  • Cho, Ki-Sook;Zaborski, M.;Slusarski, L.;Park, Soo-Jin
    • Elastomers and Composites
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    • v.38 no.2
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    • pp.139-146
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    • 2003
  • In this work, the influence of ozone treatment on surface properties of carbon black is investigated in terms of X-ray photoelectron spectroscopy (XPS) and contact angles. And their mechanical interfacial properties of the carbon black/acrylonitrile butadiene rubber (NBR) compounds are studied by the crosslink density and composite tearing energy ($G_{IIIC}$). As a result, it is found that the increasing of the ozone concentration leads to an increase of the introduction rate of oxygen-containing functional groups onto carbon black surfaces and to an increase of the surface free energy, resulting in improving both crosslink density and tearing energy ($G_{IIIC}$) of the compounds. The results can be explained by the fact that the oxygen-containing functional groups of carbon black surfaces make an increase of the degree of adhesion at interfaces between carbon blacks and rubber matrix.

Synthesis of Self-Assembled Peptide Nanoparticles Based on Dityrosine Covalent Bonds (다이타이로신 공유결합으로 자기조립된 펩타이드 나노입자의 합성)

  • Hur, Yun-Mi;Min, Kyoung-Ik
    • Korean Chemical Engineering Research
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    • v.59 no.1
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    • pp.112-117
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    • 2021
  • In this study, a method of self-assembly of peptides based on irreversible covalent bonds was studied by mimicking a biological covalent bond, dityrosine bond. A tyrosine-rich short peptide monomer having the sequence of Tyr-Tyr-Leu-Tyr-Tyr (YYLYY) was selected to achieve a high-density of dityrosine bond. The peptide nanoparticles covalently self-assembled with dityrosine bonds were synthesized by one-step photo-crosslinking of a peptide using a ruthenium catalyst under visible light. The effect of the concentration of each component for the size of the peptide nanoparticle was studied using dynamic light scattering, UV-Vis spectroscopy, and transmission electron microscopy. As a result, the synthesis conditions for size of the peptide nanoparticles ranging from 130 nm to 350 nm were optimized.

Curing behavior of Photo-Curable Materials by Photo-Shrinkage Test (광원 경화형 소재의 수축률평가를 통한 광경화 거동 평가)

  • Park, Ji-Won;Bae, Kyung-Yul;Kim, Pan-Seok;Lim, Dong-Hyuk;Kim, Hyun-Joong;Cho, Jin-Ku;Kim, Baek-Jin;Lee, Sang-Hyeup
    • Journal of Adhesion and Interface
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    • v.11 no.2
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    • pp.57-62
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    • 2010
  • Photo-curable material can be crosslinked among molecules by light source such as UV and visible light materials. Material properties are controlled by crosslink reaction. Shrinkage is occured during the curing reaction of material structure. Phenomenon of shrinkage stress occurs inside the product and reduce the stability of the product causes problems. Heat shrink the evaluation of the phenomenon has been formalized. But the evaluation of photo shrink is not enough. In this experiment, real-time contract with shrinkage tester phenomena and analysis degree of shrinkage of the material differences. According to the research, experimental results and theoretical analysis of the results were big differences. Shrinkage, especially for a number of different functional groups that were very different theory. These differences are occurred by the molecular structure different and not enough reaction.

Preparation of Polyacrylate-Based Non-Reinforced Anion Exchange Membranes via Photo-Crosslinking for Reverse Electrodialysis (역전기투석용 광가교형 폴리아크릴레이트계 음이온교환막 제조)

  • Tae Hoon Kim;Seok Hwan Yang;Jang Yong Lee
    • Membrane Journal
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    • v.34 no.1
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    • pp.70-78
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    • 2024
  • A photo-crosslinked anion exchange membrane (AEM) based on quaternary-aminated polyacrylates was developed for reverse electrodialysis (RED). Although reverse electrodialysis is a clean and renewable energy generation system, the low power output and high membrane cost are serious obstacles to its commercialization. Cross-linked AEMs without any polymer supporters were fabricated through photo-crosslinking between polymer-typed acrylates with anion conducting groups, in particular, polymer-typed acrylates were synthesized based on engineering plastic with outstanding mechanical and chemical property. The fabricated membranes showed outstanding physical, chemical, and electrochemical properties. The area resistance of the fabricated membranes (CQAPPOA-20, CQAPPOA-35, and CQAPPOA-50) were ~50% lower than that of AMV (2.6 Ω cm2). Moreover, the transport number of CQAPPOA-35 wase comparable to that of AMV, despite the thin thickness (40 ㎛) of the fabricated membranes. The RED stack with the CQAPPOA-35 membrane provided an excellent maximum power density of 2.327 W m-2 at a flow rate of 100 mL min-1, which is 15% higher than that (2.026 W m-2) of the RED stack with the AMV membrane. Considering easy fabrication process by UV photo-crosslinking and outstanding RED stack properties, the CQAPPOA-35 membrane is a promising candidate for REDs.

Variation of Adhesion Characteristics of Acryl Copolymer/Multi-functional Monomer Based PSA by UV Curing (자외선 경화에 의한 아크릴 공중합체/다관능성 단량체 복합 감압점착제의 접착특성 변화)

  • Ryu, Chong-Min;Pang, Bei-Li;Kim, Hyung-Il;Park, Ji-Won;Lee, Seung-Woo;Kim, Hyun-Jung;Kim, Kyung-Man
    • Polymer(Korea)
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    • v.36 no.3
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    • pp.315-320
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    • 2012
  • Ultra violet (UV) curable pressure sensitive adhesives (PSA) were prepared by controlling both the structure of acryl copolymer and the functionality and content of multi-functional monomers. Acryl copolymer worked as the base polymer for giving the tackiness. Multi-functional monomers were used to vary the crosslinked structure and the degree of crosslink. Acryl copolymer showed the reduced peel strength after UV curing by decreasing the content of 2-ethylhexyl acrylate in the monomer composition. Both the peel strength of PSA and the content of residue found on silicon wafer decreased after UV curing by increasing the functionality of multi-functional monomers. UV curable PSA containing 20 phr six-functional monomer showed the higher peel strength before UV curing and the lower peel strength and the least residue on silicon wafer after UV curing.