基团贡献法研究环型聚苯乙烯稀溶液流体力学参数

首次采用基团贡献法,根据内聚能、摩尔体积、摩尔吸引常数和临界特性粘数等分别计算并通过实验数据验证了环型和线型聚苯乙烯的溶度参数,特性粘数、摩尔极限粘数函数、临界分子量和Mark-Houwink参数,详细地讨论了计算大环高分子的K_(θ,r)值所取用的临界分子量应具有的理论意义。     

聚乙酸乙烯酯的溶液性质及长链支化度

用粘度法,GPC和LALLS测定了线型及不同转化率的PVAc分级级份的粘度与分子量。提出了以线型和支化聚合物的K,α计算临界分子量的方法。讨论了表征PVAc长链支化的各种参数与分子量和转化率之间的关系以及不同条件下迭代法计算的支化频率λ的差异。实验结果表明,特性粘数和数均分子量乘积所表示的流体力学体积更适合GPC的普适标定概念。     

聚苯乙烯链规整度与特性粘数的理论研究

应用构象 构型统计理论和旋转异构态模型 ,考虑大侧基对高分子链构型的影响 ,建立高分子溶液特性粘数与链无规程度的关系 ,并应用于大分子量的聚苯乙烯溶液的特性粘数的计算 ,得到特性粘数与全同、间同和无规链分子量的关系 ,并与实验结果进行比较 ,结果较为满意     

树状高分子的特性粘数与代数的关系

从爱因斯坦的粘度理论出发 ,联系树状高分子的分子结构参数 ,计算了树状高分子的特性粘数 ,得到了树状高分子的特性粘数与代数的内在关系 ,分析了树状高分子特性粘数特异行为的内在原因 ,使得对树状高分子特性粘数的理论预测成为可能     

中东常压渣油热反应过程中沥青质的缔合性变化规律

用表面张力法研究了中东常压渣油热反应过程中正庚烷沥青质缔合性的变化。测定沥青质的不同浓度甲苯溶液的表面张力,利用溶液的临界胶束浓度表征沥青质的缔合性。定义蒸气压渗透法(VPO法)测得的沥青质平均分子量和表面张力法计算得到的平均分子量之比为沥青质的缔合度参数。结果表明,随着热反应的进行,在生焦诱导期内,沥青质的临界胶束浓度下降、沥青质缔合度参数增大,缔合性增强；达到生焦诱导期后临界胶束浓度上升、缔合度参数下降,缔合性下降。     

拟合粘度曲线法研究高聚物的长链支化

本文介绍了用计算机试误法拟合粘度曲线,讨论支化参数的方法,本法可以同时确定支化临界分子量和支化程度,在此基础上可以同时得到支化参数及平均分子量、分子量分布.以聚乙烯标准参考物:SRM 1475(线型)、1476(支化物)及镍催化顺式聚丁二烯为对象介绍了上述方法.     

一点法测定特性粘数

高聚物的分子量可由溶液的特性粘数求得。特性粘数通常要从几个浓度的溶液粘度作图外推得到,这是比较麻烦费时的。为了提高测定特性粘数效率和尽快得到可靠的数据,以便指导生产实践,文献中早有从一个浓度溶液的测定数据计算特性粘数。近年来,许多人仍重视该问题的研究,并设计成了一种快速测定一个浓度溶液的粘度计和计算     

一种同时订定高分子凝胶渗透色谱校准参数和K、α常数的新方法

 ]报道一种同时订定高分子凝胶渗透色谱(GPC)校准参数和Mark常数K、α的新方法。待测高分子经粗分级，测得其特性粘数[η]和GPC谱图G1，另取一种已知K0、α0值的参考高分子也经粗分级后测得[η]和C0，1，根据普适校准关系，结合Mark方程和由Wesslan分布函数所导出的粘均分子量计算公式得到联立方程组。通过求解该方程组同时订定了高分子的GPC校准参数和K、α常数。     

二氧化碳共聚物的分子量表征(GPC和特性粘数法)

脂肪族聚碳酸酯的分子量表征问题可以从GPC数据阳特性粘数较迅速可靠地解决,同时求出其数均,粘均,重均,动力学平均分子量,及其分子量—特性粘数关联参数。为此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(dL/g)与分子量的关联。如此对聚碳酸亚丙酯和碳酸亚乙酯分别得到以下关系: ln(η)=-6.671+0.328ln(?)v+0.0186(ln(?)v)~2 (25℃,THF) (η)=6.64×10~(-5)(?)v~(0.76) (25℃, CHCl_3)     

测定零切变速度下特性粘数的简便方法

引言高分子溶液的特性粘数是一个十分重要的物理量。它和大分子的化学结构、分子量和大分子在溶液中的形态、尺寸大小等重要特性有关。特性粘数和分子量之间的联系更被广泛地利用于测定分子量。因此,如何准确而又简便地测定特性粘数值一向被人们所重视。无数实验事实表明,高分子溶液并非牛顿流体。特性粘数随切变速度的增加而下降,其下降量的大小随分子链刚硬程度、溶剂性能良好程度和分子量的增     

对甲氧基苯甲醛与N,N-二甲基甲酰胺密度黏度的测定与关联

在常压,298.15K~353.15K条件下,采用U形振动管密度计测定了对甲氧基苯甲醛-N,N-二甲基甲酰胺二元物系的密度,采用乌氏黏度计测定其黏度;并由密度和黏度数据分别计算了该二元物系超额摩尔体积VE和混合黏度的变化Δη.在不同的温度和组成下超额摩尔体积和混合黏度的变化都是负值,同时对不同温度下的超额摩尔体积与组成的关系以及混合黏度的变化与组成的关系都按Redlich-Kister方程进行了拟合,计算值与实验值的最大标准偏差小于7%.     

Synthesis and characterization of well-defined poly(tert-butyl acrylate) star polymers

Star polymers with different numbers and lengths of poly(tert-butyl acrylate) (PTBA) arms were obtained via atom transfer radical polymerization. Aliphatic alcohols with different number of hydroxyl groups varying from 3 to 6 and calix[4]arenes based on pyrogallol with 12 and 16 phenol groups were transformed to bromoester derivatives to prepare multifunctional ATRP initiators used as the cores of the stars. The star polymers were characterized by GPC with refractive index, multiangle laser light scattering and viscosimetric detectors. The molar masses of the stars reached 70,000 g/mol and the molar mass dispersities did not exceed 1.2. To elucidate the compact structure of the stars, their true molar masses were determined by GPC with triple detection (RI-MALLS-Visco) and compared with the apparent molar masses obtained from the calibration with linear poly(tert-butyl acrylate) standards. The intrinsic viscosities of the PTBA stars of the same molar mass decreased with the number of star arms but were always lower than the intrinsic viscosities of the analogue linear PTBA polymers. The values of the branching ratio g′ decreased with increasing number of arms indicating more compact structure of stars. The branching ratio g′ was correlated to the empirical predictions.     

可聚硼酸酯表面活性剂的表面化学性质及与LAS相互作用

用表面张力法研究了可聚合硼酸酯表面活性剂(BES)水溶液不同温度下(288-313 K)的表面活性和热力学函数变化；考察了BES与十二烷基苯磺酸钠(LAS)在0.5 mol·L-1 NaCl溶液中的相互作用. 结果表明, 298 K时, BES临界胶束浓度cmc达到0.066 mmol·L-1, γcmc为29.2 mN·m-1；在所考察的温度范围内BES胶束形成自由能(ΔG0m)在-22.4 - -25.8 kJ·mol-1之间, 胶束形成是熵驱动过程. BES/LAS混合体系为具有较大负偏差的非理想体系, BES/LAS分子间平均相互作用参数βm=-3.48；当溶液体相中BES摩尔分数αBES＝0.5时, 混合胶束中BES摩尔分数X1m为0.46, |βm|达到最大, 而且此时混合溶液cmc为0.017 mmol·L-1, 达到最低, γcmc为27.8 mN·m-1.     

Determination of Critical Parameters of Carbon Dioxide ＋ Butyraldehyde System with Different Compositions

Supercritical carbon dioxide（SC-CO2 ） is considered in green chemistry as a substitute for conventional solvents in chemical reactions due to its environmentally benign character. Recently we have reported the homogeneous hydroformylation of propylene in supercritical carbon dioxide（ SC-CO2 ） , which is an example of this kind of application of carbon dioxide. The determination for the critical parameters of carbon dioxide ＋ butyraldehyde mixtures is necessary for this reaction design which is the focus of the present paper. The critical parameters of the binary systems were determined via the static visual method at a constant volume with the molar fraction of butyraldehyde ranging from 1.0% to 2. 2% and the pressure ranging from 5 to 10 MPa. The experimental results show that the critical pressure and temperature increased with increasing the molar fraction of butyraldehyde. The bubble（dew） temperatures and the bubble （dew） pressures for the binary systems were also determined experimentally. The p-T Figures at different compositions of the binary systems were described. In addition, the critical compressibility factors Zc of the binary systems at different concentrations of n-butyraldehyde were calculated. It was found that the critical compressibility factor values of the binary systems decreased with increasing the molar fraction of n-butyraldehyde in the experimental range.     

Relationships for determining the rate constant of the polymerization growth reaction by means of the emulsion polymerization method

Some simple equations for the emulsion polymerization system were derived on the basis of the Smith-Ewart theory. These are used in calculating the molar monomer concentration and rate of polymerization in units of moles per liter per second for the zero-order region with respect to the monomer as well as in calculating the rate constant of the growth reaction.     

Apparent molar quantities of sodium octanoate in aqueous solutions

Densities and sound velocities of aqueous solutions of sodium octanoate were determined in a range of molalities between 0.0352 and 0.8105 mol kg^–1 at 25, 30, 35, 40 and 45 °C. The isotherms of molality dependence of both density and sound velocity were used to determine the cmcs. Apparent molar volumes and compressibilities were determined from measurements of ultrasound velocity and density. The values of apparent molar volumes and compressibilities at infinite dilution and the apparent molar quantities in the micellar range were obtained and studied as a function of temperature. Values of the critical micelle concentration and the apparent molar quantities in the premicellar and postmicellar range are discussed and compared with the values of the corresponding fluorinated compound.An erratum to this article can be found at     

Volumetric and viscosity properties of {propyl propanoate (1) + heptane (or octane) (2)} mixtures at several temperatures and correlation with the Jouyban–Acree model

Densities and viscosities of binary liquid mixtures of propyl propanoate + heptane and propyl propanoate + octane at temperatures of 278.15, 283.15, 288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15 and 323.15 K have been measured at atmospheric pressure over the entire range of composition. Using these experimental data, the excess molar volumes and the viscosity deviation have been calculated. The experimental data of density and viscosity at different investigated temperatures were mathematically represented by the Jouyban–Acree model. The mean relative deviation (MRD) was used as an error criterion, and the MRD values for data correlation of density and viscosity at different investigated temperatures are less than 0.03% and 0.50%, respectively. Excess molar volumes and viscosity deviations were correlated with Redlich–Kister equation. The calculated data point out the absence of speci?c interactions between the molecules of different components, which would be slightly weaker compared to the interactions in the pure components.     

Excess thermodynamic properties for methyl isobutyl ketone + tert-amyl alcohol system at 25°C

The excess molar volume, excess viscosity, and excess molar enthalpy were calculated from the experimental density, viscosity, and heat of mixing, respectively, at 25°C for the methyl isobutyl ketone + tert-amyl alcohol system over the complete mole fraction range. The modified UNIFAC group contribution method was used to estimate the activity coefficients which in turn were used to estimate the excess molar Gibbs free energy. Molecular interactions in this mixture were obtained from the variation of the excess functions with composition.     

反气相色谱法测定离子液体1-己基-3-甲基咪唑三氟甲磺酸盐的热力学参数

采用反气相色谱法研究了343.15~373.15 K温度范围内离子液体1-己基-3-甲基咪唑三氟甲磺酸盐([HMIM]OTF)的热力学参数。根据18种探针溶剂的保留时间计算出探针溶剂与[HMIM]OTF之间的摩尔吸附焓、无限稀释的摩尔混合焓、摩尔蒸发焓、质量部分活度系数、Flory-Huggins相互作用参数及[HMIM]OTF的溶解度参数。结果表明,所选溶剂中正构烷烃、四氢呋喃、乙醚、环己烷和苯为[HMIM]OTF的不良溶剂;二氯甲烷、丙酮、氯仿、乙酸乙酯、四氯化碳、乙酸甲酯、甲苯和甲醇为[HMIM]OTF的良溶剂;运用外推法得到了室温(298.15 K)时[HMIM]OTF的溶解度参数为20.74 (J/cm³)^0.5。本研究为离子液体的应用及相关工作提供了参考。