• 제목/요약/키워드: Chemical grafting

검색결과 175건 처리시간 0.028초

Synthesis and Non-Isothermal Crystallization Behaviors of Maleic Anhydride onto High Density Polyethylene

  • Ahn, Youngjun;Jeon, Jong Hyuk;Baek, Chul Seoung;Yu, Young Hwan;Thenepalli, Thriveni;Ahn, Ji Whan;Han, Choon
    • 한국세라믹학회지
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    • 제53권1호
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    • pp.24-33
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    • 2016
  • The grafting reaction for maleic anhydride (MA) onto high density polyethylene (HDPE) was investigated from solution process with initiators. The chemical modification of neat HDPE was carried out with various contents of MA (3-21 wt.%) and initiator (0.2-1 wt.%) at different temperature ($80-130^{\circ}C$). The grafting degree was obtained from the titration and the highest grafting degree was 3.1%. The grafting degree increased as the content of MA and initiator increased, however, the highest grafting degree was demonstrated for a particular content of MA and initiator. In the non-isothermal crystallization kinetics, the Ozawa model was unsuitable method to investigate the crystallization behavior of MA onto HDPE, whereas the Avrami and Liu models found effective. The crystallization rate was accelerated as the cooling rate increased, but postponed by combination of MA onto neat HDPE backbone.

단백질에 대한 그라프트 공중합 (제1보). Cerium (IV) 이온에 의한 비닐 단위체의 견섬유에 대한 그라프트 공중합 (Graft Copolymerization to Proteins (I). Cerium (IV) Ion-Initiated Graft Copolymerization of Vinyl Monomers to Silk Fibroins)

  • 조의환;안광덕
    • 대한화학회지
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    • 제20권4호
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    • pp.299-308
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    • 1976
  • 단백질 섬유인 견섬유에 ceric ammonium nitrate를 촉매로 사용하여 acrylamide 또는 acrylonitrile을 그라프트공중합 하였다. 공중합의 표준반응조건은 세륨염 0.025 M, acryamide 0.5 M, 초산 25%, 온도 30$^{\circ}C$, 반응시간 3시간으로 하였으며 견섬유의 욕비(bath ratio)는 1:200으로 하였다. 이상의 반응조건에서 세륨염의 농도가 0.01 M 일 때와 7% 초산수용액일 때에 그라프트율이 최대로 되었다. Acrylonitrile을 단위체로 사용하면 질산용액에서의 그라프트율이 초산수용액에서 보다 높았지만, acrylamide 사용시와는 달리 그라프트율은 현저히 낮았다. 이밖에 그라프트된 견섬유의 Lowe시약(동-글리세린 수용액)에 대한 용해도, 적외선 분석 및 분자량을 조사하고 호모 중합체의 생성에 대하여 검토 하였다.

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대기압 플라즈마 유도 그라프트 공중합으로 합성된 망상형 PU-g-PAAc 폼의 미생물 고정화능 향상 (Enhancement of Microbial Immobilization on the Surface of a Reticulated PU-g-PAAc Foam prepared through Graft Copolymerization induced by Atmosoheric Pressure Plasma Treatment)

  • 명성운;장영미;남기천;최호석;조대철
    • KSBB Journal
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    • 제19권5호
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    • pp.399-405
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    • 2004
  • A reticulated PU-g-PAAc foam was modified through the surface treatment of PU foam by one atmospheric pressure plasma. The synthesized PU-g-PAAc foam was prepared for the purpose of immobilizing microbial organisms. We also attempted different plasma treatment methods including simple plasma treatment, plasma induced grafting and plasma induced grafting followed by plasma re-treatment. The effect of grafting on equilibrium water content (EWC) of PU forms was examined by swelling measurements. Adhesion test was performed to investigate the effect of different plasma treatment methods on the improvement of microbial immobilization. Two foams modified by plasma induced grafting and plasma re-treatment after grafting showed 2.7 and 3.0 fold higher microbial immobilization than unmodified one, respectively. Meanwhile, simple plasma treatment showed a little enhancement. FT-IR analysis of each sample verified the contribution of surface functional groups on the enhancement of microbial immobilization. SEM observation confirmed microbial adherence.

감마선 자극에 의한 금속이온 이식 도전성 폴리머 (Surface Metallization of Polyethylene Films Modified by Radiation Grafting of N-vinyl Pyrollidone)

  • A. Aal;V. V. Khutoryanskiy;Z. S. Nurkeeva;G. A. Mun;Soh, Dea-Wha
    • 한국정보통신학회:학술대회논문집
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    • 한국해양정보통신학회 2003년도 추계종합학술대회
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    • pp.403-406
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    • 2003
  • Poyethylene(PE) films could be modified by radiation grafting of N-vinyl pyrollidone(NVP) using radiation. FTIR spectra was used to confirm the modification of PE films. The modified films were activated by one-step or two-step methods for electroless Cu plating. Morphology of metallized films has been investigated. Electroless Cu plating onto the modified films depends mainly on the grafting degree and activation type. The electrical conductivity and adhesion of the metallized films has been investigated and tested in regard of grafting degree of samples.

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폴리에틸렌 왁스와 무수 말레인산의 그라프팅 중합 반응에서 용매가 미치는 영향 (Effect of Solvent on the Grafting Polymerization of Polyethylene Wax with Maleic anhydride)

  • 유시원;최중소;나재식
    • 자원리싸이클링
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    • 제23권1호
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    • pp.48-57
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    • 2014
  • 본 연구에서는 고밀도 폴리에틸렌 제조공정에서 부산물로 생성되는 폴리에틸렌 왁스를 대상으로 무수말레인산을 그라프트 반응 시킬 때, 반응 용매가 가지는 성질의 영향에 대해서 조사하였다. 측정결과, 자일렌이 톨루엔보다 우수한 모노머 용해성, 팽윤성, 혼화성을 가지며, 그라프트 반응을 더욱 촉진함을 알 수 있었고, 반응 용매의 함량에 따라서는 0 ~ 200% v/w영역에서 200% v/w 조건이 최대의 그라프트 율을 보이고, 그이상의 용매가 사용될 경우에는 그라프트 율이 다시 감소하다가 일정해짐을 확인하였다. 가교도 함량 값은 용매 존재 하에 거의 생성되지 않았으며, 용매가 용매분자로 사슬이동반응 시켜 가교반응을 방지하는 것으로 판단되었다. $140^{\circ}C$에서 측정된 용융 점도 값은 폴리에틸렌 왁스에 무수말레인산이 그라프트 된 후에 증가하는 경향을 보임을 알 수 있었다.

Graft 重合에 關한 硏究-紫外線 照射에 依한 Polyvinyl alcohol 과 Styrene 의 Graft 重合에 關하여 (Studies on the Graft Polymerization-Graft Polymerization of Styrene to Polyvinyl Alcohol by Ultraviolet Light)

  • 심정섭;전경철
    • 대한화학회지
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    • 제6권1호
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    • pp.64-68
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    • 1962
  • The graft polymerization of styrene to polyvinyl alcohol using a photosensitizer(benzophenone) and ultraviolet light was studied. Styrene was grafted onto polyvinyl alcohol up to when polyvinyl alcohol was pre-immersed in water and irradiated by ultraviolet light for 24 hours styrene solution of benzophenone(0.01 molarity). The highest percentage of graft obtained in the grafting which was proceeded in the presence of water added immediately before irradiation was 29%. The grafting was proportional to irradiation time within a certain limit of time, i.e., 24 hours, and presumably was initiated at the surface. After a certain degree of grafting a definite maximum was reached. Graft polymer prepared in this experiment showed high resistance to various solvents.

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Melt-Grafting of Maleimides Having Hindered Phenol Group onto Polypropylene

  • Kim, Taek-Hyeon;Lee, Nam-Gun
    • Bulletin of the Korean Chemical Society
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    • 제24권12호
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    • pp.1809-1813
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    • 2003
  • Monomeric antioxidant 1 was prepared by the reaction of 3,5-di-tert-butyl-4-hydroxybenzyl alcohol with N-[4-(chlorocarbonyl)phenyl]maleimide in the presence of imidazole. Monomeric antioxidant 2, bearing carbamate group, was synthesized from the reaction of 3,5-di-tert-butyl-4-hydroxybenzyl alcohol and azidomaleimide. Antioxidant 3 was prepared by the reaction of N-(4-hydroxyphenyl)maleimide and 3-(3,5-ditert-butyl-4-hydroxyphenyl) propionic chloride in the presence of triethylamine. These reactive antioxidants were grafted onto polypropylene (PP) by melt-processing with free radical initiators in a mini-max moulder. From the infrared spectra of the grafted PP, it was found that the monomeric antioxidants were grafted onto PP. IR spectroscopic methods were used for the quantitative determination of the extent of grafting of monomeric antioxidant. To optimize the reaction conditions, the influences of the concentration of DCP, monomeric antioxidant, reaction time and temperature on the extent of grafting were studied.

Surface Modification of Polypropylene Membrane by ${\gamma}$ Irradiation Methods and their Solutes Permeation Behaviors

  • Shim, J. K.;Lee, S. H.;Kwon, O. H.;Lee, Y. M.;Nho, Y. C.
    • 한국막학회:학술대회논문집
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    • 한국막학회 1998년도 춘계 총회 및 학술발표회
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    • pp.99-101
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    • 1998
  • 1. Introduction : The conventional grafting polymerization technique requires chemically reactive groups on the surface as well as on the polymer chains. For this reason, a series of prefunctionalization steps are necessary for covalent grafting. The surface prefunctionalizational technique for grafting can be used to ionization radiation, UV, plasma, ion beam or chemical initiators. Of these techniques, radiation method is one of the useful methods because of uniform and rapid creation of active radical sites without catalytic contamination in grafted samples. If the diffusion of monomer into polymer is large enough to come to the inside of polymer substrate, a homogeneous and uniform grafting reaction can be carried out throughout the whole polymer substrate. Radiation-induced grafting method may attach specific functional moieties to a polymeric substrate, such as preirradiation and simultaneous irradiation. The former is irradiated at backbone polymer in vacuum or nitrogen gas and air, and then subsequent monomer grafting by trapped or peroxy radicals, while the latter is irradiated at backbone polymer in the presence of the monomer. Therefore, radiation-induced polymerization can be used to modification of the chemical and physical properties of the polymeric materials and has attracted considerable interest because it imparts desirable properties such as blood compatibility. membrane quality, ion excahnge, dyeability, protein adsorption, and immobilization of bioactive materials. Synthesizing biocompatible materials by radiation method such as preirradiation or simultaneous irradiation has often used $\gamma$-rays to graft hydrophilic monomers onto hydrophobic polymer substrates. In this work, in attempt to produce surfaces that show low levels of anti-fouling of bovine serum albumin(BSA) solutions, hydroxyethyl methacrylate(HEMA) was grafted polypropylene membrane surfaces by preirradiation technique. The anti-fouling effect of the polypropylene membrane after grafting was examined by permeation BSA solution.

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