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Two kinds of fishbone-like, β-diketone-based liquid crystalline polysilsesquioxanes(FBDKLCP'S), homopolymeric (H-FBDKLCP) and copolymeric (C-FBDKaLCP) have been first synthesized via the hydrosilylation reaction of a vinyl-terminated β-diketone with the homopolymeric ladderlike polyhydrosilsesquioxane (LPHSQ) and random copolymethylhydrosilsesquioxane (LRPMHSQ) respectively. These new kinds of FBDKLCP with M of 10~4 is thermotroic liquid crystalline polymer and its clearing temperatures T_i's and mesophase range △T's are much higher than those of the corresponding comb-like β-diketone liquid crystalline polysiloxane (DKLCP) by about 200℃. Similar results have been observed with the comparison of the two different structure Cu-coordinating compounds The significant increases in T_((?))'s and △T's of the FBDKLCP and Cu-FBDKLCP are mainly attributed to the great rigidity of the ladderlike polysilsesquioxane backbone. 相似文献
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SYNTHESIS AND-CHARACTERIZATION OF THE SOLUBLE, HIGH MOLECULAR WEIGHT AND LADDERLIKE POLYHYDROSILSESQUIOXANE AND ITS COPOLYMERS 总被引:3,自引:0,他引:3
The high molecular ladderlike polyhydrosilsesquioxane (LPHSQ) and its copolymer, ladderlike random copolymethylhydrosilsesquioxane (LR-PMHSQ) and ladderlike block copolymethylsilsesqui-oxane(LB-PMHSQ) have been synthesized by a preaminolysis reaction of the corresponding trichlorosilane with 1 ,4-phenylene diamine(PDA) then by hydrolysis and polycondensation reactions The thermographs of these polymers measured by DSC method indicate that these macromolecular backbones are very rigid as seen from the DSC curves which are almost horizontal from room temperature until 350 ~C without noticeable glass transition. The content of Si—H group in the polymers can be regulated by changing the composition of the two copolymerized monomers. So the ladderlike polymers including its copolymers can be the useful precursors for the functional polymers, especially such as fishbone-like liquid crystalline polymers. 相似文献
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Soluble, high molecular weight (MW) and ladderlike polyphenylsilsesquioxane (LPPSQ) and its copolymers, ladderlike random and block copolymethyiphenylsilsesquioxanes(LR-PMPSQ and LB-PMPSQ)have been prepared by preamminolysis, hydrolysis and polycondensation reactions. The preparation method can be carried out easily at the temperature below 95℃with high yield of 95 %, instead of the conventional way by using high-boiling solvent and any reaction activator or by precipitation with methanol. Three kinds of ladderlike polymers have been characterized. The MW's of the polymers reached to 10~6 without noticeable gelling. The scheme for synthetic route has been proposed. 相似文献
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王寿设 《核聚变与等离子体物理》1984,(2)
本文叙述了低温泵在超导磁镜装置中的应用。装置在4.2K下获得5×10~(-9)Torr的极限真空度。同时介绍了低温泵的设计、先行试验及气体在装置上的解吸特性。 相似文献
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本文报道了一台正交偏振180°旋转剪切干涉仪的工作原理和性质,并把它应用于透镜几何偏心量.轴外非对称波像差等方面的定量检测,显示了独特的功能和极高的灵敏度. 相似文献
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MOLECULAR ORIENTATION AND COLOR ALTERNATION OF SURFACE STABILIZED FERROELECTRIC LIQUID CRYSTAL CELL 下载免费PDF全文
Molecular orientation configurations across zig-zag defects and thin-line defects of the surface stabilized ferroelectric liquid crystal (SSFLC) cell are presented. The transmission spectra of the SSFLC cell of non-uniform states are numerically calculated using the asym-metric chcvron structure model. The calculations agree well with experimental results, which confirms the continuity of the N-director across the chevron interface. The color alternation of the SSFLC cell between crossed polarizers is well explained. 相似文献
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一、前言在现已出版的物理实验教材中,对高斯光束特性的研究,一般都是采用光电机械扫描的方法。如:扫描针孔、扫描刀口、扫描狭缝等等。这些方法的共同特点是移动测量元件,因而不能在同一瞬间对整个高斯光束进行测量。对于连续运转的激光器,输出光强不稳定或者是脉冲式输出的激光束, 相似文献
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A new method for the preparation of a soluble ladderlike polymethylsilsesquioxane with high molecular weight ((?)=10~5—10~6) and low molecular weight distribution (D=Mw/Mn) in common solvents instead of the formerly used toxic methylisobutylketone has been developed. The structure and macromolecular regularity were characterized by IR, X-ray diffraction, and ~(29)Si-NMR spectroscopy. The thermal property was studied by TGA and DSC. 相似文献
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