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Key engineering materials
Trans Tech Publications Ltd.
Key engineering materials

Trans Tech Publications Ltd.

半月刊

1013-9826

Key engineering materials/Journal Key engineering materials
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    Synthesis of liquid crystalline epoxy resin p-BDEPB and cure kinetics with 3-MeTHPA

    Jungang GaoCaiyun ZhangLi HuoYuanyuan Zhang...
    71-74页
    查看更多>>摘要：A liquid crystalline epoxy resin of p-biphenylene di-4-(2,3-epoxypropyloxy)benzoate (p-BDEPB) was synthesized from allyl bromide, 4-hydroxy ethyl benzoate and 4,4-dihydroxybiphenyl. Its structure and liquid crystalline behavior were characterized by DSC, 1H-NMR, FTIR, POM and XRD. The results are shown that this compound is smectic liquid crystalline.The melting point of p-BDEPB is 210 ℃ and clearing point is over 300 ℃, the epoxy value is 0.312 mol/100g. The average curing Ea of p-BDEPB/3-methyl-tetrahydrophthalic anhydride (MeTHPA) system is 97.2kJ/mol. The gel point of cured-system T_(gel) is 89.0 ℃, curing temperature T_(cu) is 132.5 ℃ and finishing temperature T_f is 146.5 ℃. The curing reaction can be described by the autocatalytic Sestak-Berggren (S-B) equation, the two reaction orders m and n is 0.23 and 0.74, respectively.
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    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Design, synthesis and properties of asymmetric substituted coronene derivative as discotic liquid crystal

    Wen-Guang WangXuYing LiuLing LiuJiaLing Pu...
    75-78页
    查看更多>>摘要：Asymmetric substituted coronenes as building blocks for preparation of materials used as functional molecular devices in the fields of self-organization, organic light-emitting diode, photovoltaic solar cell and field effect transistor are easily converted to potential interesting coronene's derivatives. A novel kind of derivative of dibenzocoronene with perylene tetracarboxdiimide as discotic liquid crystal with two kinds of soft and long chains was designed and synthesized. Its structure was confirmed by ~1HNMR and IR. Its UV-vis was measured. Its properties as discotic liquid crystal are investigated in progress.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Synthesis and mesomorphic properties of three-benzene-ring containing bent-core liquid crystal 1,3-phenylene-bis[4-(nonylcarboyloxyl) benzylideneamine]

    Yuan Ming HuangQing-Ian MaBao-gai Zhai
    79-82页
    查看更多>>摘要：A bent-core compound with three benzene-ring cores 1,3-pnenylene-bis [4-(nonylcarboyloxyl)benzyl ideneamine] was synthesized. Its mesomorphic properties were characterized with differential scanning calorimetry and polarized optical microscopy, respectively. This kind of bent-core compound exhibited mesophases in the temperature range of 155-185℃ for the first cooling but cyclic heating and cooling could lower the phase transition temperatures for this bent-core liquid crystal. Our results demonstrated that bent-core molecules with three benzene-ring cores can also form mesophases as those five benzene-ring containing bent-core molecules do.
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    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Synthesis and characterization of novel triphenylene derivatives having carboxylic acid groups at the peripheral chains

    Zhongxiao LiWei WeiWukun FanJialing Pu...
    83-89页
    查看更多>>摘要：A new kind of triphenylene derivative sym-(OC_3H_6OCOC_2H_4COOH)_6 with triphenylene at the core and carboxyl groups at the peripheral chains was synthesized and characterized by FT-IR and ~1H-NMR. Thermal gravimetry analysis (TGA) and differential scanning calorimetry (DSC) showed that these compounds have a good thermal stability, which is dependent on the flexibility and interaction of the peripheral chains. Red shifts in electronic absorption spectra of the compounds were found in solution with increasing concentration.
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    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Preparation of the polylactide copolymer by surface grafting with microspheres

    Yushun JinFei XiaoWenli GuoShuxin Li...
    90-93页
    查看更多>>摘要：The microsphere copolymer [poly(St-co-HEMA)] of monodispersed styrene and 2-hydroxyethyl methacrylate(HEMA) was synthesized by suspension polymerization. New type of hydrophobic microsphere was synthesized by surface grafting polylactic acid using the hydroxyl-terminated of poly (St-co-HEMA) as initiator. The microspheres' structures and properties were characterized by FT-IR, SEM and thermogravimetric analysis. The results have demonstrated that the copolymer [poly(St-co-HEMA)] is a random copolymer. The volume of the polylactide which was grafted with the microspheres can be controlled by changing the amount of microspheres and hydroxyl in microspheres.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Synthesis and characterization of a cholesteric liquid crystal cholesteryl nonanoate

    Yuan Ming HuangYe-tang GuoQing-Ian MaWei-wei Liu...
    94-97页
    查看更多>>摘要：A cholesteric liquid crystal cholesteryl nonanoate was synthesized and then characterized by means of differential scanning calorimetry and polarized optical microscopy. As temperature decreased from its clearing point, cholesteric phase was formed for cholesteryl nonanoate and accompanied by continuous evolution of colors in the focal conic textures. Furthermore, beautiful spherulite crystals were observed to grow out of the cholesteric phase as the crystallization continued. The evolution of the colors in recorded textures was contributed to temperature-dependent selective reflection of the liquid crystal.
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    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Synthesis and characterization of hyperbranched liquid crystalline polymer

    Chen-xi ZhangShao-rong LuJian-feng Ban
    98-101页
    查看更多>>摘要：Hyperbranched liquid crystalline polymer (HLCP) were prepared by pentaerythritol with 1,2,4-benzenetricarboxylic anhydride(BTCA) and p-hydroxy benzoic acid. The thermotropic properties, the melting point (T_m) and the isotropization temperature (T_i) of the synthesized HLCP were characterized by differential scanning calorimetry (DSC), fourier transform infrared spectroscopy (FTIR) and polarizing optical microscopy (POM). It showed that the new reactive thermotropic liquid polymer containing polyester mesogenic units exhibited thermotropic liquid crystalline properties between 140℃ and 230℃.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Synthesis and properties of linear chloroacetylated polystyrene

    Hong-chi ZhaoJuan-li GuoAi-juan SunLing-ling Gao...
    102-105页
    查看更多>>摘要：Polystyrene (PS) was synthesized by emulsion polymerization. The linear chloroacetylated PS was prepared high effectively by Friedel-Crafts acetylation of PS using chloroacetyl chloride and anhydrous aluminium chloride as chloroacetylation reagent and catalysts, respectively. The structure of chloroacetyl group is similar to that of chloromethyl group. In this method, carcinogenic compound (chloromethyl ether etc.) was avoided and the reactions of secondary cross link and multi-substitute could be eliminated. The resultant polymers were characterized by Fourier transform infrared spectrometery (FTIR) and thermogravimetric analysis. The effects of reaction conditions on chloroacetylation were studied, and the optimum reaction conditions were obtained. Chloroacetyl group was introduced into benzene ring of PS because of the appearance of the absorption peaks at 1695cm~(-1) (due to C=O bonds) and 644cm~(-1) (due to C-Cl bonds) in the FTIR spectrum. The thermal stability of the chloroacetylated PS was decreased with increasing chloroacetyl group. Moreover, there were two decomposing stages. The glass transition temperature of chloroacetylated PS increased with substitution value increasing. The effects of the reaction conditions such as reaction temperature, the solvent amount and the concentration of chloroacetyl chloride and anhydrous aluminium chloride on the chloroacetylation of PS were obvious. The certain loading can be controlled when it is lower than the maximum loading of chloroacetylated PS. The reaction condition is gentle and the operation is safe, simple and economical so that Friedel-Crafts acetylation of PS is an ideal reaction method.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Synthesis of disk-rod-disk liquid crystal trimers by using click chemistry

    Wen-Hao YuYue-Feng BaiYang JingShi-Chang Nie...
    106-110页
    查看更多>>摘要：A series of disk-rod-disk liquid crystal trimers have been synthesized. Two triphenylene discogens have been connected to a biphenyl mesogen via CuI-NEt_3 catalyzed alkyne azide cycloaddition in toluene at room temperature. The trimers have been characterized by using ~1H NMR, IR, high resolution Mass spectra and the mesomorphic properties investigated with polarized optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction. The result shows that the trimers exhibited rectangular columnar mesophase (Col_r). The length of the flexible spacer connecting the three segments has important influence on the thermal behaviors of the trimers.
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    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Synthesis of zero-birefringence polymers based on positive and negative birefringence polymer

    Wenjun YangGuozhu LiuJimin WangDuling Xia...
    111-116页
    查看更多>>摘要：Birefringence of a polymer is caused by polymer chain orientation during an injection-molding, extrusion processing or heat drawing. Birefringence of polymers degrades the performance of optical devices that require focusing by lenses or maintaining the polarization state of incident light. Optical polymers which exhibit no birefringence with any orientation of polymer chains are desirable to realize high performance optical devices that handle polarized light. In this study we demonstrate the random copolymerization method for synthesizing the zero-birefringence polymers in which positive and negative birefringence homopolymer are blended. We synthesize a polymer that exhibits no orientational birefringence with any orientation degree in a system that is composed of Methyl methacrylate/Styrene/Benzyl methacrylate.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd