共查询到18条相似文献,搜索用时 78 毫秒
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粘度法研究高分子溶液行为的实验改进(Ⅱ) 总被引:13,自引:0,他引:13
高分子在粘度计毛细管管壁上的吸附不仅会导致毛细管有效管径减小,而且可以导致毛细管界面性质发生显著改变,具体表现为测定高分子溶液流过时间t之前和之后纯溶剂的流过时间t0和t0′与高分子溶液流过时间t对浓度作图外推到浓度为零时的值t0^*并不一致。不同温度时聚乙烯吡咯烷酮(PVP)水溶液粘度测定结果表明,当吸附讷发子显著改变了毛细管界面性质时,需要将高分子溶液粘度测定方法由t/t0′改为t/t0^*。经过改进的粘度测定方法不仅更加普适合理,而且更加简单有效。 相似文献
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粘度法研究高分子溶液行为的实验改进 总被引:14,自引:0,他引:14
用Ubbelohde式粘度计测定高分子溶液粘度设备简单,操作便利,有相当好的实验精确度,是表征聚合物分子量有效手段之一,在高分子工业生产和实验室得到最广泛使用[1].它还可以用来研究高分子在溶液中的形态、高分子链的无扰尺寸、高分子链的柔性程度、支化高... 相似文献
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本文根据前文提出的高聚物溶液中大分子链尺寸的浓度依赖关系式,结合Zimm用于计算稀溶液第二维里系数的统计力学硬球模型,利用聚合物的数均分子量及其Mark-Houwink方程,计算了16种聚合物-溶剂体系在不同溶液浓度范围内的比浓渗透压。结果表明,计算值与稀溶液、亚浓溶液浓度范围内的实验值相当一致,甚至与浓溶液浓度范围内的实验值也十分接近。这显示了本法用于计算高分子溶液的渗透压是令人满意的。 相似文献
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为了更好地预测高分子溶液的汽液平衡,本文应用PSRK模型改进的混合规则[即将组合项(∑xiInb/bi)与原UNIFAC模型中的组合项(Flory-Huggins项)相抵消所获得的简化的混合规则]来计算方程的能量参数α。为了计入自由体积效应对高分子溶液的过量Gibbs自由能的贡献,在计算体积参bij时,将原混合规则中的指数修订为bij^1/2(bi^1/2 bj^1/2)/2。应用PSRK模型结合改进的混合规则预测二元高分子溶液体系的汽液平衡,结果表明新模型的计算精度是令人满意的。 相似文献
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将高聚物溶液中大分子链尺寸对浓度的依赖关系与Zimm稀溶液第二维里系数的统计力学硬球模型相结合,借助聚合物的特性粘数、Mark-Houwink方程或分子量,计算聚合物-溶剂体系在稀溶液浓度范围内π/C或H·C/τ的模拟实验值.再以π/C或H·C/τ与浓度线型回归中的始斜率求体系的第二维里系数A2,计算了30种聚合物-溶剂体系的295个不同分子量的A2值,结果均与其实验值吻合较好,且明显优于其它理论模型测算的结果. 相似文献
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Wenchao Jiang Zhaowei Hou Xiaolin Wu Kaoping Song Erlong Yang Bin Huang Chi Dong Shouliang Lu Liyan Sun Jian Gai Shichun Yao Yunchao Wang Chunlin Nie Dengyu Yuan Qinghua Xu 《Molecules (Basel, Switzerland)》2022,27(12)
Relative permeability of polymer flooding plays a very important role in oil field development. This paper aimed to measure and calculate the relative permeability curves of polymer flooding more accurately. First, viscosity variation law of polymer in porous media was studied. Rock particles of different diameters and cementing agent were used to make artificial cores and hydrophobically associating polymer solutions were prepared for experiments. Polymer solutions were injected into the cores filled with crude oil and irreducible water. In the process of polymer flooding, produced fluid was collected at different water saturations and locations of the core. Polymer solutions were separated and their viscosities were measured. With the experimental data, the viscosity variation rule of polymer transporting in porous media was explored. The result indicates that the viscosity retention rate of polymer solutions transporting in porous media has power function relationship with the water saturation and the dimensionless distance from the core inlet. Finally, the relative permeability curves of polymer flooding were measured by unsteady state method and the viscosity variation rule was applied to the calculation of the relative permeability curves. 相似文献
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亚铁离子对驱油聚合物溶液黏度的影响及其降黏机理 总被引:1,自引:0,他引:1
采用NaOH沉淀法去除胜坨油田T28区污水含有的亚铁离子(Fe2+),使配制的聚合物溶液黏度增加,通过红外光谱仪(IR)、荧光光谱仪及扫描电子显微镜(SEM)对Fe2+的降黏机理进行了分析。 结果表明,采用NaOH沉淀法处理Fe2+含量为5.9 mg/L的污水,控制pH=9,聚合物溶液的黏度可由19.17 mPa·s提高到92.50 mPa·s。 Fe2+使聚合物大分子发生断链,分子间的缔合作用减弱,破坏了分子链间形成的空间网络结构,导致溶液黏度显著降低;当用NaOH处理Fe2+后形成了Fe(OH)2沉淀而析出,同时使聚合物分子链间形成致密的空间网络结构。 相似文献
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Bernhard A. Wolf 《Macromolecular rapid communications》2007,28(2):164-170
The linear extrapolation of (η − η0)/(η0c) towards c → 0 constitutes the basis of traditional methods to determine intrinsic viscosities [η], where η is the viscosity of polymer solutions of concentration c and η0 is the viscosity of the pure solvent. With uncharged macromolecules this procedure works well; for polyelectrolytes it fails because of the pronounced non‐linearity of the above dependence at high dilution resulting from the increasing electrostatic interactions. This contribution presents a new method for the determination of [η]. It rests upon the application of the laws of phenomenological thermodynamics to the viscosity of polymer solutions and introduces a generalized intrinsic viscosity enabling a comparison of differently charged and uncharged polymers.
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从GPC和特性粘数计算高聚物各种平均相对分子质量的新方法 总被引:7,自引:0,他引:7
聚合物相对分子质量表征问题可以从GPC数据和特性粘数较可靠地迅速解决,同时求出其烽均、粘均、重均,动力学平均相对分子质量及相对分子质量-特性粘数关联参数。为些须对以往方法作较大的改进,其关键是用迭代法进行特性粘数与相对分子质量的关联。方法经用聚甲基丙烯酸甲酯验证后用于聚碳酸亚乙酯(PEC)和聚碳酸亚丙酯(PPC)分别得到关系式。 相似文献
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Muhammad R. Hashmet Mustafa Onur Isa M. Tan 《Journal of Dispersion Science and Technology》2014,35(12):1685-1690
Apparent viscosity measurements have been made to characterize the effects of shear rate and temperature on the partially hydrolyzed polyacrylamide solutions. The power-law model for the viscosity behavior has been modified to develop empirical correlations that combine effects of shear rate and temperature. Nonlinear regression was performed on the experimental data to develop the proposed correlation. The viscosities of the polymer solutions were measured in the temperature range of 25°C to 80°C, while the shear rate was varied from 1 to 1000 1/s. The proposed correlation should prove supportive for the preliminary selection of the polymers for enhanced oil recovery applications. 相似文献