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The molecular motion in polyepichlorohydrin (PEPCH), in solution and bulk, was studied by high resolution NMR by means of line width, spin-lattice relaxation time T_1 and nuclear Overhauser effect NOE. The results show that the VJGM model can describe the main chain motion of PEPCH in solution perfectly. In bulk state, the relationship between the line width and the temperature is consistent with WLF equation, but that between the high frequency molecular motion correlation time (in T_1 scale ) and temperature is consistent with Arrhenius equation. The motion parameters of PEPCH in both states were calculated. The internal rotation motion of side—CH_2Cl group was analyzed by using equal three-site jump and diffusion internal rotation model in both states. 相似文献
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In this work, the stirring induced solution crystallization behaviour of cis-1, 4-polybutadiene polymerized with rare-earth catalyst (Ln-PB) has been studied by electron microscope, DSC and GPC. It has been found that when 0.5% Ln-PB toluene solution was stirred at a temperature within the range of-15°to-79℃with a speed of 180 rpm, a kind of white swollen thread-llke substance wound around the stirrer was formed. It was seen under electron microscope that this swollen thread-Like substance consisted of fibrillar crystals of Ln-PB parallel to each other. The amount of Ln-PB wound around the stirrer increased with the decrease in crystallization temperature until a maximum was reached at about-65℃, then it decreased with the decrease in crystallization temperature. However, the higher the crystallization temperature, the higher the average molecular weight and the narrower the molecular weight distribution of Ln-PB which wound around the stirrer. Therefore, Ln-PB sample may be fractionated by stirring its dilute solution at a series of crystallization temperatures. 相似文献
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丹参酮Ⅱ-A磺酸钠(1)对治疗冠心病有较好的疗效.本文用~1H NMR方法对它在溶液中的缔合行为进行了研究,旨在为其药理提供参考. 实验称取一定量1(中国科学院药物研究所惠赠)置5mm NMR样品管中,用微量进样器加入氘代溶剂(北京化工厂产品),配成所需浓度.在XL-200超导NMR谱仪上测试,观察频率200MHz,温度20℃.D_2O中以二氧六环(3.72ppm)为内标,C_5D_5N中以残存溶剂峰(6.98,7.35,8.50ppm),DMSO-d_6和GF_3CO_2D中以TMS(0ppm)为内标.用反转恢复法测自旋晶格弛豫时间T_1,按最小二乘法自编BASIC程序在Apple微机上拟合出缔合平衡常数K. 相似文献
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The carbon-13 spin-spin relaxation times of fluorine-containing ionomers are measured and motional correlation times τ_o and τ_d are calculated by using VJGM model . The results show that the motions of polymer main chain in ionomers become more difficult with increasing of ionization degree and contents of functional group, and depend on the fine structures and stability of ionic microdomains. 相似文献
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本工作用200兆赫脉冲傅里叶变换 NMR 波谱仪测定了一系列1,2-聚丁二烯样品在溶液中~13C核自旋-晶格弛豫时间(T_1)和核Overhauser效应(NOE)。较系统地研究了1,2-聚丁二烯的分子运动与化学结构、序列结构和大分子链节构成的关系,分析了乙烯基的内旋转运动。实验结果表明,顺1,4-链节中各碳的nT_1值比1,2-链节中相应各碳的nT_1值长1倍左右;对于相同的链节,当其两旁由1,2-链节变为顺1,4-链节时,其各类碳的nT_1值都大大增加;随着1,2-链节增加,各类碳的nT_1值都明显缩短。乙烯基叔碳的nT_1值大于端碳,经计算表明,引起乙烯基叔、端碳的nT_1值不相等的主要因素是乙烯基在垂直于主链的平面上的摆动。 相似文献
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The dielectric permittivity and loss tangent of 1,2-polybutadienes with different chain structures were determined as a function of temperature from-180℃ to 100℃ at different frequencies, and the frequency and structure dependence of the dielectric propertie of 1,2-polybutadienes have been investigated. It is found that a maximum of the permittivity occurs in the glass-transition region. The width of the glasstransition peak increases with increasing frequency while its height has little change. With a rise in the content of 1,2-units, the permittivity decreases and the height of the glass-transition peak slightly grows. A maximum of the width of the glass-transition peak appears when the content of 1,2-units is about 45%. Both the permittivity and dielectric loss drop down as the growth of the content of syndiotactic 1,2-units. 相似文献
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