共查询到20条相似文献,搜索用时 109 毫秒
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热致液晶聚合物微纤与碳纤维对聚醚砜的混杂增强 总被引:2,自引:0,他引:2
热致液晶聚合物微纤与碳纤维对聚醚砜的混杂增强张洪志王育立何嘉松(中国科学院化学研究所工程塑料国家重点实验室北京100080)关键词热致液晶聚合物,碳纤维,混杂复合材料由两种或两种以上纤维增强同一种基体所得到的混杂纤维复合材料,不仅保留了单一纤维... 相似文献
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热致液晶聚酯共混物与复合材料研究 总被引:3,自引:0,他引:3
评述了热致液晶聚酯的共混物与复合材料的研究新进展,揭示了热行为与相容性、流变性与加工性以及形态结构与多种性能之间的内在联系,展望了应用于高强高模纤维与塑料、低热膨光纤涂层及低透气包装膜等高性能材料的前景. 相似文献
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本文用折射率法研究了氰乙基纤维素在二甲基甲酰胺和二甲基亚砜中形成溶致性液晶的过程,测定了临界浓度C_1~*和C_2~*。对用该方法研究高聚物液晶溶液的有效性以及折射率与其浓度和溶液结构的关系进行了探讨。讨论了各种情况下的n—C曲线。 相似文献
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热致液晶聚合物对短玻璃纤维增强聚丙烯加工性、结构与性能的改善 总被引:3,自引:1,他引:3
<正> 短切玻璃纤维增强的热塑性复合材料具有加工简便,生产周期短,可以反复加工等优点,因此得到了广泛应用。但短切玻璃纤维会给加工成型带来困难,主要在于纤维对加工设备的磨损,以及由于纤维的加入增大了熔体的粘度等。如果提高加工温度来降低粘度又会导致高聚物降解。几年前Kiss和Isayev提出用热致液晶聚合物(TLCP)的刚性棒状分子链作增强剂与被增强基体熔融共混,在加工中TLCP原位形成增强纤维,形成原位复合材料。原位复合材料中由于TLCP的流变性质,使其共混物的加工粘度 相似文献
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刚性链侧链型液晶高分子合成与研究 总被引:2,自引:0,他引:2
以自由基聚合方法,合成了一系列含有3个苯环通过酯键相联的液晶性单体及其聚合物,这类刚性液晶基元不通过柔性间隔基而直接竖挂在聚丙烯酸酯大分子主链上,具有很高的Tg·DSC及偏光显微镜结果表明,所有的单体和聚合物均为向列型热致性液晶。 相似文献
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Our studies on the nematic phase of different kinds of thermotropic liquid crystalline polymers tend to focus on the following question: what about the anisotropy of the backbone conformation in the orientational medium imposed by its mesogenic groups ? By means of small angle neutron scattering (SANS) different features are qualitatively and quantitatively discussed. In the case of liquid crystal side chain polymers, the chain anisotropy is essentially driven by thermodynamical, structural and chemical considerations. In addition, in the case of liquid crystal main chain polymers, hairpin defects are observed for sufficiently long polymers. 相似文献
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主链型液晶聚硅氧烷聚氨酯的合成及性质 总被引:12,自引:0,他引:12
合成了主链型联苯类及氧化偶氯苯类液晶聚硅氧烷聚氨酯弹性体,采用红外光谱,示差扫描量热,动态粘弹谱及带热台偏光显微镜等方法对聚合物进行了表征,讨论了它们的结构与性能.研究结果表明,这一系列多嵌段聚氨酯多数是向列型的液晶高分子聚合物,液晶相的形成同嵌段聚氨酯样品的软硬段相互作用有着密切的联系 相似文献
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Augusto Sirigu 《Liquid crystals》1993,14(1):15-36
The relevance of scientific and technical research on liquid crystal polymers is examined and compared to the overall evolution of the general field of liquid crystals. It is shown that polymers have played a progressively increasing role during the last 25 years, and although they only became a quantitatively significant subject not much more than 10 years ago, their contribution to problems and materials now represents a considerable share. Three specific topics concerning rigid rod polymers, liquid crystalline networks and polymeric metallo-mesogens are examined and some related problems highlighted. In particular, some examples showing tractable thermotropic mesomorphic systems can be obtained with linear rigid homopolymers are examined; the phase behaviour of networks derived from segmented chain mesogenic polymers is discussed; inclusion of metallo-organic groups into polymeric mesogens is reviewed. 相似文献
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采用低温溶液聚合方法,以N-(2,5-二羟基苯)亚甲基-4-取代苯胺和不同结构的二酰氯为单体,合成了两类新的高分子.聚合物的液晶行为用DSC、偏光显微镜和X射线衍射进行了表征,发现其中一类为向列型热致液晶高分子,另一类则无液晶性.随单体结构的改变,聚合物的特性粘数、熔点(Tm)和液晶态的清亮点(Ti)均呈现规律性变化。 相似文献
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新的含T-型二维液晶基元的液晶高分子的合成 总被引:4,自引:0,他引:4
采用低温溶液聚合方法,以N-(2,5-二羟基苯)亚甲基-4-取代苯胺和不同结构的二酰氯为单体,合成了两类新的高分子。聚合物的液晶行为用DSC、偏光显微镜和X射线衍射进行了表征,发现其中一类为向列型热致液晶高分子,另一类则无液晶性。随单体结构的改变,聚合物的特性粘数、熔点(Tm)和液晶态的清亮点(Ti)均呈现规律性变化。 相似文献
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Guoquan Chen Robert W. Lenz 《Journal of polymer science. Part A, Polymer chemistry》1984,22(11):3189-3201
Four closely related polyesters, with aromatic ester triads and decamethylene spacers, were prepared and characterized for their thermotropic liquid crystalline properties. Two of the polymers, which were based on linear biphenols, formed stable nematic phases, whereas one of the two based on nonlinear biphenols formed a poorly defined nematic phase; the other was not liquid crystalline. Several polymerization reactions and methods were evaluated and structure-property relationships of the polymers are discussed. The concept of “degree of liquid crystallinity” for polymers with poorly defined thermotropic behavior is considered. 相似文献
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A new series of liquid crystal polyesters with T-shaped two-dimensional mesogenic units weresynthesized by melt polycondensation of the diacetates of 2-(4'-alkoxy -phenyl)-hydroquinones with 4,4'-alkylenedioxydibenzoic acid. The polymers were characterized by using polarized microscopy, DSC and X-ray diffraction. It was realized that all the polymers have nematic thermotropic liquid crystallinecharacteristics. The melting temperature (T_m) and isotropization temperature (T_i) of the polymers changeregularly with varying lengths of the alkoxy side group and the length of the alkylene group in the main chainin company with an even-odd effect. The mesophase temperature range also varies regularly with the polymerstructure. It is shown that the mesophase range has been widened. 相似文献