高聚物高压下的状态方程

本文从高分子体系内分子链间相互作用能出发,得到了一个描述高聚物高压下的等温状态方程 从实验中发现n、m为普适常数,n=6.14,m=1,16.在不存在转变的情况下,该方程对处于玻璃态、结晶态及液态高聚物体系均适用.     

聚乳酸的非等温结晶行为

用差示扫描量热法(DSC)研究聚乳酸(PLA)从熔体及玻璃态为初始条件下的非等温结晶行为,采用Ozawa方程、Mo法、Khanna法和Kissinger法对结晶动力学参数进行计算处理。 实验结果表明,这几种方法均适合处理PLA的非等温结晶过程,而Khanna法提出的结晶速率系数(CRC)能够方便地评价PLA相对结晶速率的大小。 PLA从玻璃态升温结晶比从熔体降温结晶容易得多,升温过程有利于晶核生成,而降温有利于晶体生长。 升温结晶时,升温速率2.0 ℃/min时,结晶焓(ΔH_c)达到最大为27.1 J/g。 从熔体等速降温过程中,随着冷却速率的降低ΔH_c单调增加,冷却速率为0.25 ℃/min时ΔH_c增加到28.3 J/g。 在较低温度下从玻璃态结晶,主要表现为异相成核的二维生长方式。 在较高的温度下从玻璃态升温结晶及从熔体冷却结晶时,以均相成核的三维生长方式结晶为主。 与升温过程相比,冷却不利于晶核的生成,所以导致冷却过程总体ΔH_c偏低,扩散活化能偏大。     

高聚物双流体配位模型状态方程的简化

对高聚物以流体配位模型状态方程进行了简化，忽略了其中的Ｑ项，以简化的状态方程对４２个纯高聚物（聚丙烯、聚苯乙烯、聚异丁烯和聚丁烯－１），２种纯溶剂（苯，环己烷）和２个高聚物／溶剂混合系（聚异丁烯／苯和聚异丁烯／环己烷）进行关联，结果表明，简化的状态方程与原方程同样具有很好的关联精度和温度适用性。     

谈压缩因子图的教学

压缩因子图主要用于对实际气体的计算,它是霍根-瓦特森(Hovgen-Watson)根据气体所遵循的共同函数关系即Z=f(Pr,Tr),对多种有机和无机气体进行测定,取其平均值绘制而成的.该图能在相当大的压力范围内得到比较满意的结果,所以在工业上有很大的实用价值,特别是对于高压气体的计算.与实际气体状态方程相比较,用压缩因子图计算气体的P、V、T性质不仅方便,而且所得的数据也较为准确.此外,还可以利用类似的图形来计算逸度、比热、焓等热力学函数.笔者认为压缩因子图是物理化学课程中不可忽视的一个组成部     

测定高聚物动力学结晶能力的非等温DSC方法

研究了从非等温ＤＳＣ结晶曲线计算高聚物动力学结晶能力的方法．从高聚物非等温结晶动力学微分方程出发导出了计算高聚物动力学结晶能力的新方程．以含有不同催化剂的聚对苯二甲酸乙二酯为例，对其结晶进行了测试与计算．发现合理地选定最快结晶速率温度是计算动力学结晶能力的关键．本方法所得动力学结晶能力能正确反映高聚物的整体结晶信息     

测定高聚物结晶动力学参数的非等温理论和方法

对测定高聚物结晶动力学参数的非等温结晶理论和等速变温ＤＳＣ方法进行了讨论，文中包含了作者在此领域研究工作的最新进展。     

双流体高聚物配位溶液理论——纯物质的状态方程及其应用

以Ｆｌｏｒｙ局部组合型囚胞理论为雏形，引进空穴数，建立了更符合流体特性的双流体高聚物配位统计模型，以配位分数和局部位分数替代原局部组成中面积接触分数和局部面积接触分数概念，用拟化学近似处理局部配位分数，导出纯物质的状态方程，并应用于聚丙烯（ＰＰ）、聚丁烯－１（ＰＢＴ）、聚苯乙烯（ＰＳ）三个体系的关联，取得了良好的关联精度，根据ＰＰ和ＰＢＴ的链节结构与空穴数的关系，预言了高聚物的链节结构和空穴数与聚     

固态高聚物状态方程的研究

本文从理论上导出了一个新的三参数固态高聚物的状态方程, 在不发生转变的温度区域内, 它适用于描述固态高聚物的压强-体积-温度关系。方程形式简单, 物理参数的意义较明确。     

气体在固体表面吸附等温式的热力学理论

气体在固体表面吸附等温式的热力学理论李学良，林建新（合肥工业大学化工学院，２３０００９）气体在固体表面吸附的等温式通常可由动力学、热力学或统计力学等传统方法￣［１］导出。但通常都只针对具体模型作推导，而很少对方法作较完整的论述。本文运用热力学方法，在...     

ASPECTS OF THERMODYNAMICS OF POLYMER MIXTURES

In this brief review article some aspects of the thermodynamics of polymer mixtures are discussed, mainly based on the author's research. The studies of poly (methyl methacrylate)/chlorinated polyethylene (CPE), poly (butyl acrylate)/CPE and CPE/CPE (different chlorine content) mixture verify the "dissimilarity" and "similarity" principles for predicting miscibility of polymer mixtures. The sign of heat of mixing of oligomeric analogues is not sufficient in predicting the miscibility. The Flory equation of state theory has been applied to simulate the phase boundaries of polymer mixtures. The empirical entropy parameter Q_(12) plays an important role in the calculation, this reduces the usefulness of the theory. With energy parameter X_(12)≠0 and Q_(12)≠0 the spinodals so calculated are reasonable compared to experiments. A hole model was suggested for the statistics of polymer mixtures. The new hole theory combines the features of both the Flory equation of state theory and the Sanchez lattice fluid theory and can be reduced to them under some conditions.     

MgSiO3状态方程的分子动力学模拟

The equation of state of MgSiO3 perovskite under high pressure and high temperature is simulated using the molecular dynamics method. It was found that the molecular dynamics simulation is very successful in accurately reproducing the measured molar volumes of MgSiO3 perovskite over a wide range of temperatures and pressures. The simulated equation of state of MgSiO3 perovskite matched experimental data at up to 140GPa at 300 K, as well as the fitting data of others and results from the first-principles simulation based on the local density approximation. The simulated equations of state of MgSiO3 perovskite at higher temperatures and higher pressures also correspond to the other calculations. In addition, the volume compression data of MgSiO3 perovskite is simulated up to 120 GPa at 300, 900, 2000 and 3000 K, respectively.     

聚合物/纳米碳酸钙复合材料的制备

提出了一种制备聚合物/碳酸钙复合材料的技术.即先将纳米碳酸钙粒子在温和条件下分散到水溶液中,再在较弱的外场作用下混合分散到聚合物熔体中,使用此方法制备的4种典型聚合物(聚乙烯、聚丙烯、聚碳酸酯和聚脂)的纳米复合材料,通过扫描电镜观察纳米粒子以纳米尺寸均匀分布于树脂基体中.聚碳酸酯复合材料的相对分子质量变化不大,而且复合材料的某些力学性能有所提高,证明此种方法可用于极性与非极性聚合物制备纳米复合材料.     

Analysis of ionic liquid PVT behavior with a Modified Cell Model

High pressure pure component pressure–volume–temperature (PVT) properties of ionic liquids are summarized and analyzed with a Modified Cell Model (MCM) that uses characteristic parameters, T*, V* and P*. The model was found to provide good fits of 28 different ionic liquid PVT data consisted with 14 types cation and 10 types anion over a wide range of temperatures (278–473 K) and pressures (0.1–200 MPa). The characteristic parameters of the model could be correlated with simple functions of the Bondi van der Waals volume for the cation and anion of each ionic liquid. Generalized parameters for MCM with the van der Waals volume are proposed that allow calculation of ionic liquid densities at high pressures to within an average deviation of 1.9%.     

TS单晶体及其聚合物PTS的介电和动态力学行为

<正> 聚丁二炔类宏观单晶体以其极大的尺寸,完整性和立体规整的共轭主链,为我们提供了一个准一维体系模型化合物。它们的电性能,非线性光学性能及形成聚合LB膜的能力等具有潜在的应用前景,近年来研究工作非常活跃。丁二炔类化合物中最能培养咸大晶体,从而研究得最多的是双(对甲苯磺酸)-2,4-己二炔-1,6-二醇酯(TS)及其聚合物PTS。我们先后测量过它们的热电势率、电导、膨胀系数、介电性能、光声效     

Compressibility of CaZrO3 perovskite: Comparison with Ca-oxide perovskites

The evolution of the unit-cell parameters of CaZrO₃ perovskite, an orthorhombic perovskite belonging to space group Pbnm, have been determined to a pressure of 8.7 GPa at room temperature using single-crystal X-ray diffraction measurements. A fit of a third-order Birch-Murnaghan equation of state to the pressure-volume data yields values of V₀=258.04(2) Å³, K_T0=154(1) GPa and K₀′=5.9(3). Although CaZrO₃ perovskite does not exhibit any phase transitions in this pressure range, the compression of the structure is anisotropic with [010] approximately 20% less compressible than either [100] or [001]. Compressional moduli for the unit cell parameters are: K_a0=142(1) GPa and K_a0′=4.4(2), K_b0=177(2) GPa and K_b0′=9.4(5), K_c0=146(2) GPa and K_c0′=5.4(4). Comparison with other orthorhombic Ca-oxide perovskites shows that there is systematic increase in compressional anisotropy with increasing distortion from cubic symmetry.     

胆甾液晶／聚合物多组分体系的结构与性质的研究 Ⅱ．壬酸胆甾酯／聚（甲基丙烯酸甲酯－甲基丙烯酸丁酯）混合体系的结晶动力学研究

研究了壬酸胆甾酯与甲基丙烯酸甲酯－甲基丙烯酸丁酯无规共聚物共混体系的等温结晶动力学．讨论了共聚物组成及分子链刚性对体系中胆甾液晶组分结晶速度及成核方式的影响     

CaF2熔化温度的分子动力学模拟

The molecular dynamics method has been applied to simulate the melting temperatures of CaF 2 at elevated temperature and high pressure and to calculate the P～V equation of state of CaF 2 up to 100 GPa at 300 K. The interatomic potential was taken to be the sum of pairwise additive Coulomb, van der Waals attractions, and repulsive interactions. In addition, the shell model was used in molecular dynamics simulation. The pressure dependence of the melting temperature of CaF 2 was predicted up to 4 GPa. However, in order to account for the superheating melting of the molecular dynamic simulation, the simulated melting temperatures of CaF 2 were corrected by the modern theory of melting. Consequently, the melting temperatures of CaF 2 were accurately obtained at elevated temperature and high pressure. Therefore, it is shown that shell model molecular dynamics simulation at constant pressure indeed provides a useful tool for studying the melting temperatures of other materials under high pressures.     

Modeling of high-pressure vapor–liquid equilibrium in ionic liquids + gas systems using the PRSV equation of state

Ionic liquids are environmentally friendly solvents composed of large organic cations and relatively small inorganic anions, whose melting point is below T = 373.15 K. This is an arbitrary limit defined in order to organize the dramatically increasing number of possible applications in chemical processes. These compounds are regarded as potentially environmentally benign solvents due to their almost negligible vapor pressure, which essentially eliminates emission to the atmosphere; besides, they present a wide range of liquid existence. Ionic liquids are applicable in separation processes, such as recovery of valuable products and remotion of polluting agents in effluents 1, 2, 3 and 4 and are a new and exciting class of compounds that have the potential to overcome many of the problems associated with current CO₂-capture techniques. In this work, high-pressure vapor–liquid equilibrium (VLE) of 17 binary mixtures ionic liquid + gas has been modeled with the Peng–Robinson/Stryjek–Vera (PRSV) 5 and 6 equation of state (EoS) applying the Wong–Sandler (WS) [7] mixing rules, including the van Laar (VL) model for the excess Gibbs free energy [8] for the gamma–phi approach and the one-fluid van der Waals (VDW) mixing rules for the phi–phi approach. Critical properties and acentric factor of ionic liquids [pmim][Tf₂N] and [hmmim][Tf₂N] were determined using the extended group contribution method by Lydersen–Joback–Reid [9], while, for the other ionic liquids, these properties are available in the literature 10 and 11. Experimental data were obtained from literature 12, 13, 14, 15, 16, 17 and 18 and the adjustable parameters were fitted by minimizing the errors between predicted and experimental bubble pressure. van Laar and binary interaction parameters were regarded as temperature-dependent. The results, in terms of main deviations between experimental and calculated pressures for the 17 binary systems, are reasonably satisfactory (3.62% and 2.59% for the gamma–phi and phi–phi approaches, respectively).