• Title, Summary, Keyword: 말레이미드

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Liquid Crystalline Thermoset Films Based on Wholly Aromatic Copolymers (전방향족 공중합체의 열경화성 액정필름)

  • Moon, Hyun-Gon;Ahn, Yong-Ho;Chang, Jin-Hae
    • Polymer Korea
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    • v.34 no.4
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    • pp.369-375
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    • 2010
  • We used melt polymerization method to prepare a series of aromatic liquid crystals (LCs) based on aromatic ester and amide units with the reactive methyl-maleimide end group, and then the resulting thermally cross-linked LCs to produce LC thermoset films by means of solution casting and the followed heat treatment. The synthesized LCs and LCTs were characterized by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), thermomechanical analysis (TMA), X-ray diffractometry (XRD), and polarizing optical microscopy (POM) with a hot stage. All of the LCs prepared by melt polymerization method formed smectic mesophases. The thermal properties of the LC and LCT films were strongly affected by the mesogen units in the main chain structures. The thermal expansion coefficients of samples were in the range of 27.72~50.95 ppm/$^{\circ}C$.

Gas Permeability of Polymeric LB Films Containing Imidazole-Metal Ion Complexes (이미다졸-금속 이온 착체를 포함하는 고분자 LB막의 기체 투과성)

  • 김병주;이범종
    • Polymer Korea
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    • v.24 no.4
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    • pp.453-458
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    • 2000
  • The permeability of oxygen and nitrogen was investigated from the polymeric LB films containing imidazole-metal ion complexes and compared with its corresponding cast films on porous membrane filters. The amphiphilic polymer, poly(N- (2-(4-imidazolyl)ethyl)-maleimide-alt-1-octadecene) (IM-O), was synthesized by reaction of poly(maleic anhydride-alt-1-octadecene) with histamine. The IM-O nonolayer showed high stability on Fe (III) ion-containing subphase. The molecular structure in the LB films was investigated by means of FT-IR spectroscopy. The metal ion concentration incorporated into the LB films was determined by means of XPS measurements. The mechanical stability and uniformity of the LB films on porous substrates were indirectly evidenced by SEM observation. The LB and cast films showed more or less higher selectivity toward nitrogen, and high permeability was found to both the oxygen and nitrogen.

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Thermal Melt Grafting of Maleimides Having UV-absorber onto Polypropylene (폴리프로필렌에 UV 흡수제를 갖는 말레이미드의 용융그래프팅)

  • Kim, Taek Hyeon;Na, Hye-Sun
    • Polymer Korea
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    • v.38 no.1
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    • pp.49-53
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    • 2014
  • A novel monomeric UV-absorber was prepared by the reaction of 2,4-dihydroxybenzophenone with N-4-chlorocarbonylphenylmaleimide in the presence of triethylamine. This reactive maleimide was grafted onto polypropylene (PP) by the thermal melt-processing in a mini-max-moulder. IR spectroscopic method was used for the quantitative determination of the extent of grafting of monomeric maleimide. To find the optimal reaction conditions, the dependence of reaction temperature and time and the concentration of monomeric UV-absorber was investigated on the grafting yields. The photooxidative effect of the grafted PP was evaluated in the weatherometer comparing to the PP mixed with UV-absorbers using the carbonyl index of IR spectrum. The grafted PP showed an excellent anti-photooxidative effect.

Morphology and Properties of PP/PU Blends Prepared by Compositional Quenching (Compositional Quenching으로 제조한 PP/PU 블렌드의 모폴로지 및 물성)

  • Lim, Gyeong-Taek;Ju, Min-Hyuk;Kim, Do-Heyoung;Song, Ki-Chan;Kim, Su-Kyung
    • Elastomers and Composites
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    • v.36 no.3
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    • pp.177-187
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    • 2001
  • Polypropylene(PP)/polyurethane(PU) blends with reactive compatibilizers were prepared by the compositional quenching process. Maleic anhydride grafted PP(MPP) and hydroxyethyl maleimide grafted PP(HPP) were introduced as reactive compatibilizers. The formation of HPP and the reactions of compatibilizers with the PU components were confirmed by FT-IR spectroscopy. The morphology, tensile properties, thermal stability, and surface property were studied. The blends prepared by the compositional quenching showed better dispersed domain morphology than the melt blends. The PU domain size became more uniform and reduced in size with increasing the amount of compatibilizers. The blends with HPP showed sightly smaller domain sire than the blends with MPP. The blends with compatibilizers all showed improved tensile properties, surface property. and thermal stability due to the interfacial adhesion effect. The blends with MPP showed higher surface energy than the blends with HPP, but the latter showed better thermal stability compared to the former.

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Synthesis and herbicidal activities of heterocyclic PPO inhibitor derivatives substituted with epoxy groups (Epoxy Group이 치환된 헤테로고리형 PPO 저해제의 합성과 제초활성)

  • Jeon, Dong-Ju;Park, Kwaun-Yong;Park, Chang-Min;So, Won-Young;Kim, Hyoung-Rae;Song, Jong-Hwan;Hwang, In-Taek
    • The Korean Journal of Pesticide Science
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    • v.9 no.2
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    • pp.181-184
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    • 2005
  • The heterocyclic PPO inhibitor compounds have been studied due to their potent herbicidal effects without toxic to human and animals. We have designed and synthesized 4,5,6,7-tetrahydroindazole, maleimide, and tetrahydrophthalimide compounds carrying diverse epoxide substituents at 5- position of the phenyl group. Their herbicidal activities were evaluated under submerged paddy conditions. These results showed that 4,5,6,7-tetrahydroindazole compounds gave potent herbicidal activities especially to ECHOR, MOOVA, and CYPSE at a relatively low rate of 16 g/ha and improved tolerance on rice compared to S-275 as a standard herbicide in this experiment.

Synthesis and Characterization of Wholly Aromatic Polyester Liquid Crystalline Thermosets (전방향족 폴리에스터 열경화성 액정의 합성과 특성)

  • Moon, Hyun-Gon;Jung, Myung-Sup;Chang, Jin-Hae
    • Polymer Korea
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    • v.36 no.1
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    • pp.9-15
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    • 2012
  • We prepared a series of aromatic liquid crystals (LCs) based on wholly aromatic ester units with the reactive end group methyl maleimide by means of melt condensation method, and the resulting LCs were thermally crosslinked to produce liquid crystalline thermoset (LCT) films. The synthesized LCs and LCTs were characterized with Fourier transform infrared (FTIR) spectroscopy, wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), thermomechanical analysis (TMA), and polarizing optical microscopy (POM) with a hot stage. The glass transition temperature ($T_g$) and coefficient of thermal expansion are strongly affected by the mesogen units in their main chain structures. The $p$-substituted biphenyl LC was found to have the highest thermal property value.

Chemical Modification and Feedback Inhibition of Arabidopsis thaliana Acetolactate Synthase (아라비돕시스 탈리아나 Acetolactate Synthase의 화학적 변형과 되먹임 방해)

  • Hong, Seong-Taek;Choi, Myung-Un;Shin, Jung-Hyu;Koh, Eun-Hie
    • Applied Biological Chemistry
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    • v.40 no.4
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    • pp.277-282
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    • 1997
  • Acetolactate synthase (ALS) was partially purified from Escherichia coli MF2000/pTATX containing Arabidopsis thaliana ALS gene. The partially purified ALS was examined for its sensitivity toward various modifying reagents such as iodoacetic acid, iodoacetamide, N-ethylmaleimide (NEM), 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB), p-chloromercuribenzoic acid (PCMB), and phenylglyoxal. It was found that PCMB inhibited the enzyme activity most strongly followed by DTNB and NEM. Since iodoacetic acid did not compete with substrate pyruvate, it appeared that cysteine is not involved in the substrate binding site. On the other hand, the substrate protected the enzyme partly from inactivation by phenylglyoxal, which might indicate interaction of arginine residue with the substrate. The partially purified enzyme was inhibited by end products, valine and isoleucine, but not by leucine. However, the ALS modified with PCMB led to potentiate the feedback inhibition of all end products. Additionally, derivatives of pyrimidyl sulfur benzoate, a candidate for a new herbicide for ALS, were examined for their inhibitory effects.

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