• Title, Summary, Keyword: photo-polymerization

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Comparative Study of Physical Properties of Functional Ophthalmic Hydrogel Lens Using Photo and Thermal Polymerization

  • Kim, Duck-Hyun;Seok, Jae-Wuk;Sung, A-Young
    • Journal of the Chosun Natural Science
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    • v.10 no.3
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    • pp.148-153
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    • 2017
  • In this study, HEMA, MMA, AA, and EGDMA were used as basic combinations for manufacturing hydrophilic lenses for ophthalmic applications. In addition, AIBN (thermal polymerization initiator), 2H2M (photo polymerization initiator), and 3-hydroxypyridine (additive) were used to manufacture hydrophilic ophthalmic lenses through thermal polymerization and photo polymerization before their physical properties were measured. The results showed that when ophthalmic lenses were prepared via thermal polymerization and photo polymerization using 3-hydroxypyridine as an additive, their optical and physical properties and surface structures were different in each case, but they all satisfied the physical properties required for ophthalmic lenses.

Photo polymerization-induced Hybrid Alignment of Nematic Liquid Crystal for Roll to Roll Fabrication

  • Kim, Kyoung-Sun;Kwon, Soon-Bum;Lee, Ji-Hoon
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.623-624
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    • 2009
  • Here we report a photo polymerization-induced hybrid alignment of a nematic liquid crystal cell which can be applied for a roll to roll fabrication process. Predominant polymerization in the vicinity of UV incident front induced a diffusion of monomers toward front slide and anisotropic polymer network was formed parallel to the polarization direction of the UV light. This induced planar alignment of liquid crystals at the front slide. Simultaneously, homeotropic alignment was induced at the bottom slide as the polymers are phase-separated from a bottom slide.

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Photo-Induced Cationic Ring-Opening Polymerization of 4-Methylene-2-styryl-1,3-dioxolane by Benzylsulfonium Salt

  • Park, Jaekyeung
    • Macromolecular Research
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    • v.9 no.4
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    • pp.206-209
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    • 2001
  • One of the approaches to obtain functional polymer is polymerization of a monomer having two functional groups. Although polymerization of a monomer having two different types of functional group is general, the author has been interested in the polymerization of a monomer having two similar types of functional group. This work shows the preparation and selective polymerization of 4-methylene-2-styryl-1,3-dioxolane having two similar reactive double bonds via cationic polymerization at ambient temperature. Cationic ring-opening polymerization of 4-methylene-2-styryl-1,3-dioxolane using benzylsulfonium salt as a photo-initiator quantitatively afforded high molecular weight of poly(keto-ether).

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Monitoring photo-polymerization reaction using near-IR spectroscopic technique (Near-IR 분광법을 이용한 광 경화 중합반응 관찰)

  • Chung, Soo-Chung;Hong, Jin-Who;Yu, Jeong-A
    • Analytical Science and Technology
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    • v.15 no.4
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    • pp.341-345
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    • 2002
  • The extent of UV-curing photo-polymerization reaction was monitored by near-IR spectroscopic method. Acrylates containing quaternary ammonium salts and Darocur 1173 were used as reactive monomer and a photo initiator, respectively. The extent of photo-polymerization reaction was obtained from the conversion ratio of acrylate double bond calculated from the intensities of measured bands at 1615 nm and at 2105 nm. Near-IR spectroscopic methods can be an useful tool for the monitoring of the progress of photo-polymerization.

Photo-induced Living Cationic Polymerization of Vinyl Ethers in the Presence of Diphenyliodonium Salts(I) (Diphenyliodonium염 존재하에서 비닐 에테르의 광양이온 리빙 중합(I))

  • Kwon, Soonhong;Lee, Youngsung;Jeon, Hyunjeong;Mah, Soukil
    • Textile Science and Engineering
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    • v.39 no.4
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    • pp.377-382
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    • 2002
  • Photo-induced living cationic polymerization of isobutyl vinyl ether (IBVE) has been newly developed in the presence of diphenyliodonium iodide (DPII). Zinc iodide was used as an activator in the polymerization reaction. A linear relationship between % monomer conversion and the number average molecular weight of the resulting polymer reveals the living nature. The increase in both the polymer yield and its molecular weight until the original monomer was exhausted reveals that the propagating cationic species have the long lifetime due to the absence of termination or chain transfer process. It became also evident that a PIBVE-based block copolymer can be obtained by the subsequent monomer addition technique from this photo-induced system. The effects of various factors such as concentrations of DPII and zinc iodide, temperature, and duration of photo-irradiation were also discussed.

Chemical Vapor Deposition Polymerization of Poly(arylenevinylene)s and Applications to Nanoscience

  • Joo, Sung-Hoon;Lee, Chun-Young;Kim, Kyung-kon;Lee, Ki-Ryong;Jin, Jung-Il
    • Bulletin of the Korean Chemical Society
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    • v.27 no.2
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    • pp.169-184
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    • 2006
  • A review is made on the chemical vapor deposition polymerization (CVDP) of insoluble and infusible poly(arylenevinylene)s and its applications to nanoscience. Poly(p-phenylenevinylene) (PPV), poly(naphthylenevinylene)s, poly(2,5-thinenylenevinylene) (PTV), and other homologous polymers containing oligothiophenes could be prepared by the CVDP method in the form of films, tubes, and fibers of nano dimensions. They would be readily converted to graphitic carbons of different structures by thermal treatment. Field emission FE) of carbonized PPV nanotubes, photoconductivity of carbonized PPV/PPV bilayer nanotubes and nanofilms also were studied.

New Method of Injectable Hydrogels by Novel Photo-polymerization

  • Lee, Seung-Young;Tae, Gi-Yoong
    • Proceedings of the Polymer Society of Korea Conference
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    • pp.252-252
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    • 2006
  • Utilizing the existence of the induction period in photo-polymerization, we propose a new injection method of photo-polymerizable, thermocrosslinking hydrogels made of di-acrylated Pluronic F127 (DA-PF127). This method can solve the problem of fast dissolution of thermal gelation as a scaffold and the disadvantages of the existing injection method that photo-polymerize di-acrylated Pluronic polymer after injection using optical fiber. Injectable gelation of DA-PF127 by the proposed method was demonstrated both in vitro and in vivo. The enhanced stability by this novel photo-polymerization strategy was confirmed by the more sustained release of loaded protein as well as the prolonged degradation time of the hydrogels.

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Investigation of Electro-optical Characteristics in A-TN-LCD on Poly(vinyl)cinnamate Surfaces (Poly(vinyl)cinnamate막을 이용한 A-TN-LCD의 전기광학 특성)

  • 서대식;박지호;이보호
    • Electrical & Electronic Materials
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    • v.10 no.6
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    • pp.576-580
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    • 1997
  • In this paper, the viewing angle characteristics of amorphous (a) - twisted nematic (TN)-liquid crystal display (LCD) on poly(vinyl)cinnamate (PVC) surface with UV (ultraviolet) light irradiation were investigated. It was found that the threshold voltage increases with increasing the polymerization of PVC surfaces. We observed that the domain size of a-TN-LCD decreases with increasing the photo polymerization by increasing UV light irradiation time on PVC films. Also, we observed that the viewing angle of a-TN-LCD increased with increasing the photo polymerization on PVC surfaces. Finally, we consider that the viewing angle of a-TN-LCD on PVC surfaces is large compared to a-TN-LCD on polyimide (PI) surface.

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Investigation of Electro-optical Characteristics in a-TN-LCD on Poly(vinyl)cinnamate Surfaces (Poly(vinyl)cinnamate막을 이용한 a-TN-LCD의 시야각특성에 관한 연구)

  • Seo, Dae-Shik;Park, Ji-Ho;Lee, Chang-Hun;Lee, Bo-Ho
    • Proceedings of the KIEE Conference
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    • pp.1588-1590
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    • 1997
  • The viewing angle characteristics of amorphous(a)-twisted nematic(TN)-liquid crystal display (LCD) on poly(vinyl)cinnamate (PVC) surfaces with photo polymerrization were investigated. It was found that the threshold voltage increases with increasing the polymerization of PVC surfaces. That the domain size of a-TN-LCD is affected by the surface crystallization with increasing the photo polymerization of the photo-alignment film. We observed that the viewing angle of a-TN-LCD increased with increasing the photo polymerization on PVC surfaces. Finally, we consider that the viewing angle of a-TN-LCD on PVC surfaces is large compared to a-TN-LCD on polyimide(PI) surface.

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