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液晶聚合物从结构上可分为3种:侧链型、主链型和主侧链型。侧链型液晶聚合物主要是聚丙烯酸酯类、聚硅氧烷类以及磷腈聚合物类。Gray等对聚丙烯酸酯类含不同取代基的联苯结构液晶聚合物进行了研究,结果表明无间隔基且取代基为氰基和饱和脂肪基时,该聚合物呈现近晶型液晶行为。为了增加介晶单元的长径比及刚性,本文在聚甲基丙烯酸酯侧链 相似文献
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在电场和磁场下手性侧链丙烯酸酯液晶聚合物的行为江雪平金顺子漆宗能张树范(中国科学院化学研究所北京100080)关键词手性侧链丙烯酸酯液晶聚合物,红外二向色性,液晶分子排列含有手性液晶基团的聚合物,分子中含有不对称碳原子,在一定条件下使液晶聚合物... 相似文献
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以横向取代的液晶基元为侧基合成了聚甲基丙烯酸酯,并对此聚合物进行初步表征.在玻璃化温度(170℃)以上样品进入液晶态.样品较高的玻璃化温度以及能形成液晶态的特性被认为是棒状液晶基元使聚合物分子链刚性化的结果. 相似文献
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以含硝基偶氮苯侧基的丙烯酸酯液晶聚合物为研究对象,利用DSC、WAXD、偏光显微镜等手段研究了分子结构对侧链液晶聚合物结晶行为的影响.结果表明:丙烯酸酯类液晶聚合物的晶区是由介晶基团的规整排列形成的,大分子主链和柔性间隔基不参与结晶.随着柔性间隔基长度的增加,晶区分子排列有序性提高,结晶度增大;非晶共聚组分MA含量的增加,限制了介晶基团的有序排列,当MA含量超过83%后,只得到非晶共聚物. 相似文献
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基于聚烯烃用成核剂的结构特征设计合成了两种极性基团和非极性基团交替排列的乙烯基单体,并利用自由基引发聚合,制备出相应的侧链型液晶聚合物.采用元素分析、红外光谱和核磁共振氢谱对所合成单体和聚合物的结构进行了确认.并采用热失重(TGA)和差示扫描量热仪(DSC)研究了聚合物的热稳定性和相转变温度.结果表明,所合成聚合物的起始热分解温度均在337℃以上,具有优异的热稳定性;液晶相变温度区间可达186 K,具有较宽的液晶态温度范围.热台偏光显微镜(HS-POM)研究结果表明,聚合物均呈现出纹影织构,证明所合成的聚合物均为热致向列型侧链液晶高分子.采用DSC和HS-POM研究了所合成的侧链液晶聚合物对高密度聚乙烯(HDPE)异相成核结晶行为的影响.结果表明,侧链型液晶聚合物在提高HDPE结晶温度、结晶度以及降低HDPE晶粒的尺寸及分布方面均有优异的效果,是一类HDPE有效的成核剂. 相似文献
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A series of crosslinked liquid crystalline polymers and the corresponding uncrosslinked liquid crystalline polymers were prepared by graft copolymerization; their liquid crystalline properties were characterized by DSC, POM and X-ray measurements. The results show that the crosslinking obtained in the isotropic state leads to a reduction of the clearing point (Tc) of the crosslinked polymers, as compared with the corresponding uncrosslinked polymers. The crosslinked polymers with low crosslinking density (P1-P7) exhibit nematic mesogenic phases, as do the uncrosslinked polymers. In contrast, a high crosslinking density leads to the crosslinked polymers P8 and P9 losing their thermotropic liquid crystalline phases; they instead exhibit stress-induced orientation. 相似文献
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new series of sulfur-contalning side chain liquid crystalline polymers were described. Mesomorphic side chains with methylene spacer in different length have been synthesized and their structures were identified by NMR, IR and MS.The liquid crystalline nature of the polymers was characterlzed by microscopy.The Polymers have liquid crystalline nature. 相似文献
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Chiral liquid crystalline polymers containing biphenylene and azobenzene as the mesogensand S(-)-2-methyl-1-butanol as the chiral end group were synthesized and characterized by DSC,POM and X-ray diffraction. These polymers show crystalline or glassy liquid crystalline phase atroom temperature. Most polymers show smectic A or highly ordered smectic phases abovemelting temperature. 相似文献
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This paper reviews structure-property relations in liquid crystalline side group polymers, as investigated by X-ray scattering of fibres, by small angle X-ray scattering in solution, by dielectric relaxation measurements and by melt rheology, as well as synthetic ways to “combined liquid crystalline polymers”. The synthesis of liquid crystalline elastomers from side group, main chain and combined liquid crystalline polymers is described. First structure-property relations are discussed. 相似文献
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Yusuke Kawakami 《Macromolecular Symposia》1994,84(1):167-181
Novel side-chain liquid crystalline polymers were synthesized based on the molecular design of the chemical structures of main-chain, spacer, and mesogenic groups. The main-chain structures are polyether, by the cationic ring-opening polymerization of oxetane derivatives, and polydiene, by the radical polymerization of diene derivatives. Some of the polymers from oxetanes with various mesogen and spacer groups show smectic liquid crystalline phase. Both cyano- and fluorine-substituted biphenyls are good mesogenic groups in these liquid crystalline polymers. Polydiene also acts as a novel main-chain to give smectic liquid crystalline state with cyanobiphenyl or fluorobiphenyl as a mesogen. Not only oligomethylene groups but also siloxane and oligo(oxyethylene) groups act as a component of the spacer groups to give liquid crystalline state. 相似文献
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使用HBIRheomix610型混合机将四种全芳香族热致液晶聚合物与热塑性树脂熔融共混,研究了混合效果,混合过程的平衡转矩与时间,温度的关系,结果显示,用该混合机可以得到均匀分散的共混体系,这些液晶聚合物具有大大低于纯聚砜的熔体粘度,将其与聚砜熔混,可使其混体系的平衡转矩比纯聚砜减小2-3倍,说明液晶聚合物是一种加工助剂,能用来改善高性能工程塑料的加工性能。 相似文献
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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_m (except that with substituent of methoxy) and the clearing temperature T_i of the polymers change regularly with varying of the length of the alkyl substituent groups. 相似文献
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新型液晶聚合物的分子设计及功能 总被引:3,自引:0,他引:3
介绍了新型液晶聚合物的分子设计方法;综述了利用分子间氢键,电荷转移相互作用和防子间相互作用设计得到的新型液晶聚合物复合体系的性质和功能,概述了液晶聚合物LB膜和液晶聚合物弹性体的分子排布特征和功能,这些研究开拓了液晶聚合物研究的新领域,为液晶聚合物分子排布的控制和功能性研究提供了新方法。 相似文献