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As a typical water-soluble polymer, ultra-high molecular weight (UHMW) partially hydrolyzed polyacrylamide (HPAM) has been widely used in various industries as thickeners or rheology modifiers. However, precise determination of its critical physical parameters such as molecular weight, radius of gyration (Rg) and hydrodynamic radius (Rh) were less documented due to their high viscosity in aqueous solution. In this work, the molecular structure of five UHMW-HPAM samples with different MW was elucidated by 1H and 13C NMR spectroscopy, and their solution properties were characterized by both static and dynamic light scattering. It is found that all the second virial coefficient (A2) values are positive and approaching zero, indicating of a good solvent of 0.5 M NaCl for UHMW-HPAM. The weight-average molecular weight (Mw) dependence of molecular size and intrinsic viscosity [η] for these series of HPAM polymers with MW ranging from 4.81 to 15.4 × 106 g·mol−1 can be correlated as Rg = 3.52 × 10−2Mw0.51, Rh = 1.97 × 10−2Mw0.51, and [η] = 6.98 × 10−4 Mw0.91, respectively. These results are helpful in understanding the relationship between molecular weight and coil size of HPAM polymers in solution, and offer references for quick estimation of molecular weight and screening of commercial UHMW-HPAM polymers for specific end-users. 相似文献
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Viscoelastic properties of binary blends of polystyrenes with a narrow distribution of low and high molecular weights (M2 > M1 > Mc) were examined. By combining the theoretical work of Montfort et al., Kurata, and Schausberger, a binary blending law was developed and was used to calculate the zero shear viscosity and steady state compliance of the blend of two monodisperse polymers. The blending law was also used to calculate the molecular weight distribution of a polydisperse polymer. The calculated results were compared with those obtained from viscoelastic ] and GPC measurements, with good agreement. 相似文献
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采用毛细管黏度计法测定超高相对分子质量聚乙烯(UHMWPE)的特性黏数([η]),对[η]的准确测定的影响因素进行了探讨。结果表明:以十氢萘为溶剂,使用前进行蒸馏提纯;在配制UHMWPE溶液时,加入质量分数为0.2%的抗氧剂1010,按预溶胀、溶胀、溶解3步骤进行溶解,溶解温度150℃,溶解时间0.5 h,配制UHMWPE溶液浓度为100~600 mg/L;严格控制温度(135±0.2)℃,所测UHMWPE的[η]平行性较好,相对标准偏差为1.08%。 相似文献
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结合PET生产检验实例,使用方差分析发现特性黏度数据之间存在显著性差异,而使用国标中离群值检验判别法发现离群值的判定结论相反,在结论矛盾的基础上分析指出应正确识别系统误差及随机误差,合理应用各种检验方法,同时指出离群值判定方法与方差分析的结合使用有助于提高离群值判定的科学准确性。 相似文献
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聚酯特性粘数测试方法的比较 总被引:1,自引:0,他引:1
阐述了相对粘度仪法和传统玻璃毛细管粘度仪法的测试原理,实验验证了Y501相对粘度仪和LAUDACD30粘度仪测试结果的差异性。结果表明其差异性不大,相比LAUDACD30粘度仪,5(501相对粘度仪的测试精度及自动化程度更高、有利环保,更具有实用性和快捷性。 相似文献
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分别用乌氏黏度计和旋转黏度计测定了氯化聚丙烯甲苯溶液的特性黏数和黏度,把特性黏数和黏度进行关联,发现ηsp/C与浓度C(ml/g)的关系用多项式ηsp/C=[η]+k1[η]2C+k2[η]2C2拟合,可以得到很好的结果。并且用特性黏数和Mark-Houwink方程求出了不同氯化聚丙烯(CPP)的黏均分子量。 相似文献
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Molecular weight and the Mark‐Houwink relation for ultra‐high molecular weight charged polyacrylamide determined using automatic batch mode multi‐angle light scattering
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This study presents an automatic batch mode (i.e., off‐line) multi‐angle light scattering (MALS) method for the molecular weight (MW) determination of ultra‐high MW (UHMW) polyacrylamide (PAM) homopolymer and acrylamide copolymers. This method combines a MALS detector with a sample dilution and injection device that automatically delivers a concentration gradient from a stock solution. The automation makes it practical to use the batch MALS method for routine MW analysis of UHMW polymers. The automatic batch MALS analyses of a series of poly(sodium acrylate‐co‐acrylamide) (30:70 mol %) in 1.0M NaCl show a non‐linear Mark‐Houwink relation in the MW range of 1.2 × 106 to 12.6 × 106 g mol?1. The entire molecular weight range can be fit with a quadratic relation or two linear equations, one for molecular weight up to 5.3 × 106 g mol?1 and the other from 5.3 × 106 to 12.6 × 106 g mol?1. The non‐linear Mark‐Houwink relation suggests that the extrapolation of the Mark‐Houwink equation beyond the measured MW range into the UHMW regions can significantly overestimate the MW of the UHMW polymers. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43748. 相似文献
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The dependence of shear and elongational viscosity on the molecular weight of poly(vinylidene fluoride) has been studied using a capillary rheometer. The elongational viscosity was evaluated based on Cogswell's method with two types of capillaries: capillary length (L)/capillary diameter (D) = 10 mm/1 mm and L/D = 0 mm/1 mm. We used the ratio P0/PL that indicates the contribution of elongational flow to the total flow involving both the shear and elongational flows. PL and P0 are the pressure losses in the capillary and the converging flows, respectively. P0/PL increased with molecular weight and shear rate. This corresponds to decreasing the number of entanglements of molecular chain under a large displacement, especially high shear. Thus, we suggest using P0/PL as the parameter of the entanglement interaction on the molecular chain under a large displacement. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2381–2384, 1999 相似文献
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Udaya S. Toti Krishna S. Amur Mahadevappa Y. Kariduraganavar Lata S. Manjeshwar Mrityunjaya I. Aralaguppi Tejraj M. Aminabhavi 《应用聚合物科学杂志》2002,83(2):283-290
Experimental viscosities were measured by Schott Gerate viscometer at 30 °C for polystyrene–chloroform and polycaprolactum–benzene systems. These data were analyzed by a newly developed analytical method to calculate intrinsic viscosity and viscosity constants. The analytical method was compared with the graphical as well as the least squares methods and the new analytical method is better than the graphical method because it avoids personal errors that might arise in reading the intercept and slope values from the reduced viscosity versus concentration plots. Furthermore, the analytical method is as effective as the least squares method, but provides better insights while choosing the experimental viscosity values. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 283–290, 2002 相似文献
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用红外吸收光谱对两性聚丙烯酰胺结构进行了表征,表明分子链上丙烯酰胺(AM)、甲基丙烯酰氧乙基三甲基氯化铵(MADQUAT)和丙烯酰胺基甲基丙磺酸钠(NaAMPS)链节的存在。随后研究了NaCl、CaCl2浓度及pH值对不同阴阳离子度的聚合物特性粘度的影响。结果表明,AM-MADQUAT-NaAMPS共聚物特性粘度受CaCl2浓度影响较NaCl大,但总的来说耐盐性比单性离子聚合物好,且其特性粘度在很大范围内(除等电点附近)不受pH值的影响。 相似文献
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叙述了在落实聚酯切片特性粘度国家标准的过程中出现的一些问题 ,讨论了特性粘度分析误差的主要来源于测试仪器、所用试剂、过滤设施等 ,并提出了解决办法。 相似文献
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Within the context of a generalized coupling model we can support the hypothesis that, while the mode of relaxation for self diffusion (D) and shear flow (η) are the same, the entanglement interactions are different. We assume that there are two distinct coupling parameters nD and nη for self diffusion and shear flow respectively. The model predicts the molecular weight and temperature dependences to be scaled by the relevant coupling parameters as: for melts with Arrhenius temperature dependences. We have found that nn=0.43 and 0.42 for polyethylene (PE) and hydrogenated polybutadiene (HPB) which scale η as M3.5 and M3.4. Also the apparent flow activation energies of 6.35 kcal mole?1 for PE and 7.2 kcal mol?1 for HPB scale to primitive activation energies Ea of 3.6 and 4.2 kcal mole?1 for PE and HPB respectively. On the other hand the M?2 dependence of D results in nD=1/3. Then the reported activation energies for self-diffusion in PE and HPB of 5.49 and 6.2 kcal mole?1 scale to primitive activation energies of 3.7 and 4.1 kcal mole?1, respectively. 相似文献
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聚酯的特性黏度与聚合度 总被引:1,自引:0,他引:1
通过测定的聚酯特性黏度计算确定其聚合度是聚酯生产控制的关键环节 ,为此列举了目前国内厂家测定聚酯特性黏度的几种不同溶剂体系及其特性黏度的计算方法 ,并通过介绍质量比为 3 / 2的苯酚 四氯乙烷溶剂体系的特性黏度与分子质量的关系式 ,着重说明通过特性黏度计算聚酯聚合度的方法。 相似文献
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An alternative method for determination of intrinsic viscosities is described which evolves from the application of l'Hǒpital's rule to the expression defining the intrinsic viscosity. The method yields independent evaluations of the intrinsic viscosity and does not involve extrapolation beyond the range of experimental data or rely on a theoretical expression associated with such extrapolations. The application of the method is illustrated and comparisons are included with the results obtained by traditional approaches. 相似文献
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开发了一种新的特性粘数分析方法 ,该方法采用熔体流动时间计算特性粘数 ,与经典特性粘数分析方法有很好的相关性且具有分析时间短、费用低、无污染等优点。 相似文献
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测试条件对瓶级聚酯切片特性黏度的影响 总被引:2,自引:0,他引:2
比较了GB T1793 1 1999标准、ISO162 8 5 :1998和ASTM460 3 96标准的测试条件。按照GB T1793 1 1999中规定的 2种方法对样品的特性黏度进行测试。试验了溶剂体系、测试温度、计算公式及黏度计毛细管直径对黏度测试结果的影响。瓶级聚酯切片标准样品在质量比为 1 1的苯酚 邻二氯苯溶剂中测试的特性黏度结果比在质量比为 3 2的苯酚 /四氯乙烷溶剂中的结果高 0 .0 5 ;在 2 5℃与 3 0℃下测试的结果相差 0 .0 13左右 ;用 2个计算公式得出的特性黏度结果有明显差异 ;而黏度计毛细管的直径影响不大 ,d为 0 .84~ 0 .95mm能满足试验精度要求。但毛细管直径选定后 ,不要轻易改变 ,以确保系统误差稳定。 相似文献