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SYNTHESIS AND CHARACTERIZATION OF liquid crystal polymerS WITH T-SHAPED TWO-DIMENSIONAL MESOGENIC UNITS

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Chinese Journal of polymer Science 1996年第1期14卷 71-79页

作者：李自法陈志军张淑媛曹少魁周其凤 Mater. Eng. Dept. Zhengzhou Univ. Zhengzhou 450052 Chem. Dept. Peking Univ. Beijing 100871

Two series of new liquid crystalline polymers with T-shaped two-dimensional mesogenic units were synthesized by low temperature solution polycondensations of 4-substituted N-2, 5-dihydroxybenzylidene aniline monomers with different diacyl dichlorides. The polymers were found to be nematic and shown liquid crystalline behavior. The melting temperature T-m and the clearing temperature T-i of the polymers change regularly with varying of the monomer structures.

关键词： liquid crystal polymer T-shaped two-dimensional mesogenic unit N-2, 5-dihydroxybenzylidene-4-substituted aniline

STUDY ON liquid crystal polymerS WITH TWO-DIMENSIONAL MESOGENIC UNITS

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Chinese Journal of polymer Science 1993年第4期11卷 58-63页

作者：张春晓李自法周其凤周洪兵 Chem. Dept. Zhengzhou Univ. Zhengzhou 450052 Chem. Dept. Peking Univ. Beijing 100871

A series of liquid crystalline polymers with two-dimensional mesogenic units were synthesized by solution polycondensation at low temperature. All the polymers were liquid crystalline. The melting temperature T;（except that with substituent of methoxy） and the clearing temperature T;of the polymers change regularly with varying of the length of the alkyl substituent groups.

关键词： liquid crystal polymer Two-dimensional mesogenic unit N-2 ', 5 '-dihydroxy benzylidene-4-alkoxyaniline Monotropic nematics

Design and synthesis of liquid crystal copolyesters with high-frequency low dielectric loss and inherent flame retardancy

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Chinese Chemical Letters 2023年第5期34卷 621-625页

作者： Shi-Yu Zhang Teng Fu Yue Gong De-Ming Guo Xiu-Li Wang Yu-Zhong Wang State Key Laboratory of polymer Materials Engineering The Collaborative Innovation Center for Eco-Friendly and Fire-Safety Polymeric MaterialsNational Engineering Laboratory of Eco-Friendly Polymeric Materials(Sichuan)College of ChemistrySichuan UniversityChengdu 610064China

Ultra-low dielectric loss(Df)and low dielectric constant(Dk)materials are urgently required in highspeed and large-capacity transmission,in which the wholly aromatic liquid crystal polymer(LCP)has gained attention due to its excellent dielectric ***,the relationship between molecular structure and dielectric properties is still not *** this study,two copolyesters containing phenyl or naphthyl structures are synthesized,as well as the effects of benzene and naphthalene mesogens on dielectric properties are *** synthesized copolyesters containing naphthalene structure have good comprehensive properties with high thermal stability(T_(5%)=479℃ and T_g=195-216℃),inherent flame retardance(LOI=33.0-35.0 and UL-94 V-0 level at 0.8 mm),low Dk(2.9-3.0@10 GHz)and low Df(0.0027-0.0047@10 GHz).Naphthalene mesogen can reduce the dielectric loss more significantly than benzene at high frequency by reducing the density and mobility of polarizable groups,which leads to the effectively limited dipole polarization in ***,we proposed a new strategy for designing low Dk and low Df materials.

关键词： liquid crystal polymer Low dielectric loss Low dielectric constant Naphthalene structure Flame retardant

SYNTHESIS AND CHARACTERIZATION OF MAIN CHAIN AROMATIC liquid crystal COPOLYESTERS WITH X-SHAPED AND ROD-SHAPED MESOGENIC UNITS

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Chinese Journal of polymer Science 1998年第1期16卷 48-55页

作者：李自法李磊张淑媛郑世军曹少魁赵丽婷周其凤 Department of Materials Engineering Zhengzhou University Zhengzhou 450052 China Dept. of Polym. Sci. and Eng. the College of Chemistry Peking Univ. Beijing 1000871 China

A series of main chain liquid crystal aromatic copolyesters with X-shaped and rod-shaped mesogenic units were synthesized via solution condensation polymerizations of 4,4'-(alpha,omega-octanedioyloxy)-dibenzoyl dichlorides with 2,5-bis(p-octanoxy benzoyloxy)-hydroquinone and diphenol. All of the copolyesters showed thermotropic liquid crystalline behaviors through observations using DSC, polarized microscopy and X-ray diffraction. The melting point (T-m) and the isotropization temperature (T-i) change regularly with varying the content of diphenol unit in the copolymers.

关键词： liquid crystal polymer X-shaped and rod-shaped mesogenic units aromatic copolyester synthesis and characterization

SYNTHESIS AND PROPERTIES OF liquid crystal POLYSILOXANES WITH MESOGENIC STILBENE SIDE GROUPS

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Chinese Journal of polymer Science 2000年第2期18卷 95-99页

作者： Dong Zhang Yan-tao Zhu Da-hui Zhao Xin-hua Wan Qi-feng Zhou Department of polymer Science & Engineering, College of Chemistry, Peking University, Beijing 100871, China 北京大学北京

A variety of mesomorphic side-chain polysiloxanes were synthesized by using hydrosilylation reaction with dicyclopentadienylplatinum(II) (DPPC) as the catalyst. The mesogenic groups are derivatives of stilbene with cyano or nitro tail groups. The products were characterized by DSC, X-ray diffraction and polarizing optical microscopy (POM). All the polymers were found to have relatively low T-g and can form a smectic liquid crystal phase.

关键词： liquid crystal polymer polysiloxane

Phase Behavior of the Ternary Solution Involving Rodlike and Random Coil polymers

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Chemical Research in Chinese Universities 2000年第2期16卷 163-168页

作者： LIN Jiaping WU Herong LI Shijing 华东理工大学上海 2 0 0 2 37

The present paper covers the phase behavior of poly(pbenzamide)(PBA)/Nylon 6/H 2SO 4 and poly(pphenylene terephthalamide) (PPTA)/Nylon 6/H 2SO 4 systems. The transition temperatures detected by the Depolarized Light Intensity measurements were used to construct the phase diagram in which the influence of temperature was shown. The enhanced depolarized light intensity observed in the ternary system suggests that the coil polymer chains may tend to be extended and contribute to the overall anisotropy of the liquid crystal phase.

关键词： Phase diagram Phase transition liquid crystal polymer

THE EFFECT OF SUBSTITUENT ON THE THERMAL PROPERTIES OF POLYESTERS CONSISTING OF AROMATIC TYPE SCHIFF BASE MESOGENIC UNITS AND POLYMETHYLENE SPACERS

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Chinese Journal of polymer Science 1995年第1期13卷 51-58页

作者： Amar H.Al-Dujaili Iman F.Mustafa Amir T.Atto Department of Chemistry College of Education Ibn Al-Hytham University of Baghdad Baghdad P. O. Box 7358 IraqDepartment of Chemistry College of Education Ibn Al-Hytham University of Baghdad Baghdad P. O. Box 7358 IraqDepartment of Chemistry College of Sciences University of Sadaam Baghdad Iraq

Polyesters consisting of substituted aromatic type Schiff base mesogenic unit andpolymethylene spacers were synthesized and their thermal transitions and liquid crystallineproperties were studied. The liquid crystalline behaviour has been characterized by differentialscanning calorimetry (DSC) and optical polarizing microscopy. Structural broadening bysubstitution of methoxy group in 2, 2' positions of the mesogenic core produce polymers withlower transition temperatures. polymers synthesized from ortho and meta substituted phenylenediamine did not form a liquid crystal phase.

关键词： liquid crystal polymer Polyesters Aromatic type schiff base Mesogenic units Spacers

THEORY OF INTRAMOLECULAR ORIENTATIONAL ORDER OF MESOGENIC UNITS IN MC-LCPS AND ITS APPLICATION

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Chinese Journal of polymer Science 1993年第4期11卷 17-25页

作者：王晓工刘德山周其庠 Department of Chemical Engineering Tsinghua University Beijing 100084Department of Chemical Engineering Tsinghua University Beijing 100084Department of Chemical Engineering Tsinghua University Beijing 100084

New concepts such as intramolecular orientational order parameter and corresponding model as well as theory were proposed to describe the intramolecular orientation of mesogenic units in the liquid crystalline polymer chains. The relationship between the intramolecular orientational order parameter and the molecular geometrical parameters such as the bond angle, the bond rotational angle and the rotational potential energy of chemical bonds was deduced. A significant even-odd oscillation of the intramolecular orientational order parameter of LCPs with different length of flexible spacer was found and rationally related to even-odd zig-zag manner of transition properties The verification and application of the theory are also discussed. The isotropic transition temperature predicted by the theory is shown to be in favourable agreement with the experiments.

关键词： liquid crystal polymer Intramolecular orientation order parameter, Theory.

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Preface

Chinese Journal of polymer Science 2000年第3期18卷 5-5页

作者： Mao Xu Jun-jing Wang

A variety of mesomorphic side-chain polysiloxanes were synthesized by using hydrosilylation reaction withdicyclopentadienylplatinum (Ⅱ) (DPPC) as the catalyst. The mesogenic groups are derivatives of stilbene with cyano or nitrotail groups. The products were characterized by DSC, X-ray deffraction and polarizing optical microscopy (POM). All thepolymers were found to have relatively low T_g and can form a smectic liquid crystal phase.

关键词： liquid crystal polymer Polysiloxane