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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 and characterization of a new organometallic palladium coordinated liquid crystal

    Jianqiang LiuXingcheng ZhangYouyong DaiHongdi Xiao...
    117-121页
    查看更多>>摘要：A new organometallic palladium coordinated liquid crystal that is written by PdS4 has been synthesized by chelating reaction of the tetrachloropalladate (PdCl_4~(2-)) and the star-like liquid crystal (S4) containing four butoxyazobenzene mesogens in its periphery. The structure and liquid crystallinity (LC) of PdS4 were characterized by infrared absorption spectroscopy (IR), ultraviolet absorption spectra (UV), nuclear magnetic resonance spectroscopy (NMR), elemental analysis (EA), polarizing optical microscope (POM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The phase behavior of PdS4 is Crl67N232I200N170Cr, its melting point and clearing temperature are higher than those of the free azo ligand S4, its mesophase range is broader than S4's. It will be used as a new type photoelectric functional material in the future.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Influence of the terminal substituent of azobenzene on the liquid crystalline property of ABA triblock copolymers

    Xinde TangLongcheng GaoNianfeng Han
    122-125页
    查看更多>>摘要：The influence of the terminal substituent of azobenzene on the liquid crystalline property of ABA triblock copolymers was studied. Three kinds of azobenzene-containing monomers with different terminal substituents were respectively used to synthesize ABA triblock copolymers (denoted as PMMAzo_(12)-PEG_(13)-PMMAzo_(12), PEMAzo_(14)-PEG_(13)-PEMAzo_(14), and PNMAZO_(14)-PEG_(13)-PNMAZO_(14)) by atom transfer radical polymerization (ATRP). These copolymers were characterized with 1H NMR and GPC, and exhibited controlled molecular weights and narrow molecular weight distributions. Differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) have shown that these copolymers have mesophases. PMMAzo_(12)-PEG_(13)-PMMAzon has a smectic mesophase and a nematic mesophase, while both PEMAzo_(14)-PEG_(13)-PEMAzo_(14) and PNMAzo_(14)-PEG_(13)-PNMAzo_(14) have a nematic mesophase. This demonstrates that the LC properties of these copolymers highly depend on the terminal substituent of azobenzene.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Synthesis and properties of thermotropic liquid crystalline polyesters with flexible polymethylene spacer

    Wei zhong LuChun WeiQiushan Gao
    126-131页
    查看更多>>摘要：Polymethylene bis(p-hydroxybenzoates) were prepared from methyl p-hydroxybenzoate and different diols by melted transesterification reaction. Three liquid crystalline polyesters were synthesized from terephthaloyl dichloride and polymethylene bis(p-hydroxybenzoates). Its structure, morphology and properties were characterized by Ubbelohde viscometer, Fourier transform infrared spectroscopy (FT-IR), Differential scanning calorimetry (DSC), polarized optical microscopy (POM) with a hot stage, and wide-angle X-ray diffraction (WAXD). Results indicated that the intrinsic viscosities were between 0.088 and 0.210 dL/g. Optical microscopy showed that the TLCP has a highly threaded liquid crystalline texture and a high birefringent schlieren texture character of nematic phase and has wider mesophase temperature ranges for all polyesters. DSC analysis were found that the melting point (T_m), isotropic temperature (T_i) of TLCPs decreased and the temperature range of the liquid crystalline phase became wider with increased number of methylene spacers in the polyester. The WAXD results showed that TLCPs owned two strong diffraction peaks at 29 near 19° and 23°.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Synthesis of novel discotic hexa-peri-hexabenzocoronene derivatives and the Influence of substituents on properties

    Xu-Ying LiuWen-Guang WangJia-ling Pu
    132-134页
    查看更多>>摘要：Due to hexa-peri-hexabenzocoronene (HBC)'s perfect structural and their promising electronic and optoelectronic properties, the novel derivatives of HBC have continuously attracted interest. Hexaphenylbenene, as a necessary precursor to synthesize HBC, is affected by the substituents during dehydrocyclization. New synthetic strategy of some HPC derivatives with long-chain ester groups is described. Their structures were established by ~1H nuclear magnetic resonance (~1HNMR) and infrared spectrometry (IR), ultraviolet-visible spectrograph (UV-vis). The results indicate that the substituents play an important role on oxydehydrogenation of HPCs.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Synthesis and mesomorphism of semi-fluorinated chain liquid crystals with [1,2,3]-triazole rings

    Yang YangKe-Qing ZhaoWen-Hao YuBi-Qin Wang...
    135-139页
    查看更多>>摘要：Series of semi-fluorinated chain liquid crystals with [1,2,3]-triazole rings have been synthesized with CuI-Et_3N catalyzed alkyne-azide cycloaddition reaction. The selectively produced 1,4-disubstituted regioisomers were characterized by using IR, NMR, and Mass. The mesomorphic behaviors were characterized with polarizing optical microscopy and differential scanning calorimetry. Compounds with perfluorinated chains have showed smectic A phase.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Bimetallomesogens: synthesis and mesomorphic properties of coppercomplexes of 3,3'-(2-hydroxypropane-1,3-diyl)bis(azan-1-yl-1 -ylidene)bis(2-(4-alkoxyphenyl)prop-1 -en-1 -ol)

    Chun-Jung ChenChung K. Lai
    140-143页
    查看更多>>摘要：A new type of 3,3'-(2-hydroxypropane-1,3-diyl) bis(azan-1-yl-1-ylidene)bis(2-(4-alkoxy phenyl)prop-1-en-1-ol) and their copper complexes were prepared and mesomorphic properties characterized. The mesomorphic properties of these copper complexes were studied by differential scanning calorimetry (DSC), polarized optical microscopy (POM) and powder X-ray diffraction. X-ray structural crystallographic analysis showed that these bimetallic compounds have two copper centers coordinated with central square planar geometry. These molecules all have total two 1a or five alkoxy sidechains 1b appended around the central core. The mesomorphic behavior exhibited was found to be dependent on the sidechain density. All compounds in 1a exhibited smectic mesophases, however, compounds in 1b exhibited hexagonal columnar phases (Col_h), which were characterized by optical textures and confirmed by powder x-ray diffraction.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Synthesis and properties of liquid crystalline polyurethanes from 4,4-bis (6-hydroxyhexoxy) biphenyl and 3,3'-dimethyl-4, 4'-biphenylene diisocyanate

    Xiao-Dong ChenNan-Qiao ZhouHai Zhang
    144-149页
    查看更多>>摘要：A thermotropic liquid crystalline polyurethane (LCPU) was synthesized by the polyaddition reaction of 3,3'-dimethyl-4,4'-biphenylene diisocyanate (TOD1) with 4,4-bis(6-hydroxyhexoxy)biphenyl (BHHBP). The liquid crystalline behavior of the polymer was investigated by differential scanning calorimetry (DSC), polarized optical microscopy (POM), wide angle X-ray diffraction (WAXD). The LCPU exhibited a nematic phase with a threaded texture and had a wide mesophase temperature range. And thermogravimetric analysis (TGA) indicated the decomposition temperature of the LCPU was >300℃. The observation of POM showed that the LCPU was a thermotropic nematic liquid crystalline polymer at certain temperature range.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Properties of poly(4-hyderoxybenzoate) oligomer and its blends with poly(trimethylene terephthalate)

    Mingtao RunXiaomin HuMeibo SunWeitao Ma...
    150-153页
    查看更多>>摘要：The poly(4-hydroxybenzoate) (PHBA) oligomer was synthesized by using the monomer of 4-acetoxybenzoic acid (PABA), and its blends with poly(trimethylene terephthalate) (PTT) are prepared by melt-blending at 250℃ in nitrogen. Their chemical structure characterization and crystal morphology were investigated by using the fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (~1HNMR), and polarizing optical microscopy, respectively. The results suggest that PHBA oligomer with 3 polymerization degree was synthesized and it is a thermotropic liquid crystal with the nematic characteristics. When the blends crystallize from melt, because the rigid oriented PHBA molecules becomes the nucleating agents for PTT molecules' crystallization, much transcrystalline layers formed in the blends, although the crystalline PTT/PHBA blends show spherulites morphology character without observing nematic LC phase.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    A_2BA_2-type amphiphilic liquid cystalline block copolymers by ATRP: synthesis and characterization

    Xinde TangNianfeng HanJing Xu
    154-157页
    查看更多>>摘要：A_2BA_2-type amphiphilic liquid crystalline block copolymers containing azobenzene were synthesized by atom transfer radical polymerization (ATRP). The macroinitiator prepared by the esterification reaction between poly(ethylene glycol) (PEG) and 2,2-dichloroacetyl chloride was used to initiate the ATRP of 6-[4-(4-ethoxyphenylazo)phenoxy]hexyl methacrylate (M6C). The resulting macroinitiator and block copolymers were characterized by H NMR, gel permeation chromatography (GPC). Polarizing optical microscopy (POM) and differential scanning calorimetry (DSC) preliminarily revealed the liquid crystalline property of these block copolymers. These novel amphiphilic liquid crystalline block copolymers are promising in some areas, such as optical data storage, optical switch, and molecular devices.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Synthesis and characterization of biphenylnate liquid crystalline polyurethanes

    Jian-feng BanShao-rong LuChen-xi Zhang
    158-161页
    查看更多>>摘要：A series of novel biphenylnate liquid crystalline polyurethanes (BLCPs) were synthesized by polyaddition reaction of 4,4'-dihydroxybiphenyl with 2,4-TDI(2,4-toluenediisocyanate) and diethylene glycol through changing the molar ratio of diphenol and diol. The thermotropic properties, the melting point (T_m) and the isotropization temperature (T_i) of the synthesized polyurethanes were characterized by FT-IR, DSC, POM and WXRD. The results of experiments showed that all of the polyurethane polymers exhibited thermotropic liquid crystalline properties between 130℃ and 230℃. The transition temperature (T_m and T_i) decreased with an increase in the length of the flexible chain.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd