Corresponding states correlation for thermal conductivity of dense fluids

The simple principle of corresponding states may be generalized to include substances that depart from strict conformality by introducing state dependent shape factors. This approach is applied to thermal conductivity, and a general correlation is presented for the shape factors. Mixing rules derived from statistical mechanics, based on Enskog dense gas theory for thermal conductivity, provide a means for predicting thermal conductivities of dense gas and liquid mixtures of nonpolar substances. Results obtained are generally within experimental error.     

Kinetically stabilized metastable polarization states in ferroelectric ceramics

By directly using experimental hysteresis loop data, a Landau theory-based model has been developed to investigate the effects of externally applied stimuli (electric field, stress, and temperature) on the average, time-dependent response in ferroelectric ceramics. For both PLZT and BNT-BT-KNN systems, experimentally observed (macroscopic) metastable states are a result of a free energy minimum that develops at a zero polarization state when the sample is subject to an externally applied field. Additionally, the frequency dependent hysteresis response demonstrates that a transition between relaxor ferroelectric and antiferroelectric develops at a critical cycling frequency, in agreement with the literature. The appearance of frequency-induced and electric field amplitude-induced kinetically stabilized phases is proposed and summarized in terms of frequency-stress and frequency-temperature response maps.     

甲基苯基二乙氧基硅烷饱和蒸汽压的测定与关联

静态法测定了甲基苯基二乙氧基硅烷在378.10—423.84 K之间的饱和蒸汽压数据。采用非线性回归的方法得到Antoine常数A,B,C的值分别为8.809 9,3 935.933,87.61,饱和蒸汽压的计算值与实验值之间的误差介于0—2.36%;在2.27—101.325 kPa之间,沸点计算值与文献值的绝对误差不超过3.80 K,以开尔文温度表示的最大相对误差不超过0.77%。通过Clausius-Clapeyron方程计算得到甲基苯基二乙氧基硅烷在378.10—423.84 K之间的平均摩尔蒸发热为50 653.79 J/mol,常压沸点为494.66 K。     

甲基二苯基乙氧基硅烷饱和蒸汽压测定与关联

通过减压精馏的方法得到高纯度的甲基二苯基乙氧基硅烷,使用精馏法测定了甲基二苯基乙氧基硅烷在0.04—23.03 kPa范围内的饱和温度数据。采用非线性回归方法,利用EVIEWS 5.0软件得到甲基二苯基乙氧基硅烷的Antoine常数A,B,C的值分别为7.026 9,2 372.59和181.47,安托尼方程计算出的饱和蒸汽压与实验数据的误差在0—5.56%之间,与文献值的误差不超过7.41。通过Clausius-Clapeyron方程计算得到甲基二苯基乙氧基硅烷在373.20—512.23 K范围内平均摩尔蒸发热为72 942.96 J/mol,常压沸点为556.20 K。     

Densities of hydrocarbons in their saturated vapor and liquid states

The Sum and differences of the saturated vapor and liquid densities of 23 hydrocarbons were used to develop the following reduced density relationships for these saturated states The hydrocarbons considered included n-parafins, olefins, diolefins, naphthenes, and aromatics. Constants β, γ, and δ, and exponent n were found to be dependent on,. Equation (a) can reproduce liquid densities with an overall average deviation of 1.1 % over the entire temperature range, while Equation (b) was found to apply only in the interval 0.900 ≤ T_R ≤ 1.00 with an average deviation of 2.2%. For temperatures of T_k < 0.90, the saturated vapor density was found to depend on temperature as follows where k and m were also found to be Z_c dependent. Values calculated using Equation (c), when compared with 81 available experimental densities for 12 hydrocarbons, produced an average deviation of 3.0%.     

Corresponding states relationship for electrical resistivity of glassy polymers

Using the glass transition as a corresponding state for polymers, a relationship has been found between reduced electrical resistivity and reduced temperature for a large number of polymers in the glassy state. As a consequence of this relationship and the Arrhenius temperature dependence of the unreduced data, the activation energy for electrical conduction is shown to be directly proportional to the glass transition temperature and linearly related to the activation energy for the glass transition. A molecular model is proposed to explain these results in terms of the number of polymer segments involved in electrical conduction (～10) and the activation energy per segment (～4 kcal/mol).     

Detonation properties of saturated hydrocarbons

Calculated and experimental data on the most important parameters of combustion and detonation of saturated hydrocarbons C _n H _2n+2 (from methane to eicosane) in mixtures with oxygen and air in wide ranges of initial parameters (pressure, temperature, fuel concentration, and its phase state) are presented.     

Saturation and metastable properties of the van der waals fluid

Modern applications require accurate thermodynamic equations of state that portray stable and metastable states of fluids. Earlier work has shown that the famous van der Waals equation, contrary to widely held views, finds its natural niche in the rank of real substances ordered according to their values of the acentric factor. In this note, the saturated and metastable state properties of a van der Waals fluid are presented in the form of a temperature table and a pressure table. A comparison of these results with the available data for mercury is made and it is established that mercury is approximated rather well as a van der Waals fluid.     

1,1,1-三氟-2,3-二氯丙烷饱和蒸汽压的测定与关联

采用静态法,测定了1,1,1-三氟-2,3-二氯丙烷(HCFC-243db)在293.59—400.80 K温度区间的饱和蒸汽压数据,并用Antoine方程ln p=A-B/(T+C)进行关联,确定了蒸汽压方程的3个参数A,B,C的值分别为17.205,5 485.902和90.276。Antoine方程计算得到的饱和蒸汽压与实验数据吻合较好,相对误差在-1.05%—2.88%之间。通过Clausius-Clapeyron方程计算得到HCFC-243db在293.59—400.80 K范围内的平均摩尔蒸发热为28 326.222 J/mol,通过Antoine方程计算得到的常压沸点为345.12 K。     

Molecular structure and driving force to metastable states: Janus faces in polymer crystallization

This paper is a retrospective of a past dedicated to research on polymers and a situation sketch of the present and the near future. (Co)polymers discussed are mainly based on ethylene. (Cross‐)fractionation techniques combined with state‐of‐the‐art characterization techniques, like quantitative differential scanning calorimetry, are powerful tools for the study of the links between two main topics: molecular structure and crystallization/melting. These form the two ‘Janus faces’ polymers can show, namely Face 1: the molecular structure resulting from polymerization with the keyword ‘nature’; and Face 2: the driving force of crystallization towards a metastable state, with the keyword ‘nurture’. After all, to meet demands for properties of products, in principle one starts with a given molecular architecture, after which dedicated processing, including application of temperature–time ramps, has to do the job. With new instrumentation, especially fast scanning (chip) calorimetry, for the first time in history the driving force towards crystallization into one of the possible metastable states – via Face 2 – can be controlled, of course within certain limits given by Face 1. This promising outlook of combining the faces to a useful symbiosis of Janus will be a challenge for those working in the science of crystallization of polymers. © 2018 Society of Chemical Industry     

高精度全氟甲烷R14饱和蒸汽压测定及关联

在141.76—225.71 K温度条件下,运用高精度(温度精度为±0.01 K,压力精度为±0.01%)可视化汽液相平衡装置测量了30组全氟甲烷(R14)的饱和蒸汽压实验数据,并分别运用Wagner方程,朱明善提出的改进Wagner方程及项-谭提出的方程对实验数据进行拟合。对计算值和实验数据进行对比分析,前2个方程计算结果较为接近,朱明善改进型方程略优,项-谭提出的方程误差最大。通过拟合得到上述温度范围内的较高精度的饱和蒸汽压方程。     

烟酸在水中的溶解度及介稳性质的研究

介稳区宽度(MSZW)是结晶过程设计的重要参数,为了得到高纯度大颗粒的烟酸晶体,应将结晶条件控制在介稳区内。测定烟酸在293.15—323.15 K下的溶解度,并用Apelblet经验方程关联,与实验值相比有较好的拟合效果,相对偏差在0.66%以下,平均偏差为0.27%;以溶解度数据为基础,计算了烟酸的溶解热力学参数。另外,通过聚焦光速反射测量(FBRM)技术测定烟酸的介稳区宽度,研究了降温速率、搅拌速率和晶种加入量对介稳区宽度的影响,研究发现,较小的降温速率、较大的搅拌速率以及加入晶种都会使介稳区宽度变窄;适当增大晶种数目,可以有效调节介稳区。溶解度及介稳区的测定,为生产过程工艺放大以及结晶器的设计提供数据支撑。     

Preparation and properties of polyurethane acrylates modified by saturated alcohols

Polyurethane acrylates (PUAs) modified by saturated alcohols were synthesized by saturated alcohols, isophorone diisocyanate (IPDI), 2-hydroxyethyl acrylate (HEA) and polycaprolactone triol (PCL). The molecular structures were identified by Fourier transform infrared (FTIR) spectroscopy. Real time infrared (RTIR) spectroscopy was used to investigate the conversion vs. irradiation time plots of photopolymerization of synthesized PUAs. The volume shrinkage was measured by using laser displacement sensor (LDS). The adhesion in the glass, polycarbonate (PC) and polyvinyl chloride (PVC) substrates was tested by the laser micrometer and universal testing machine. The glass-transition temperature (Tg) and storage modulus (E′) were measured by dynamic mechanical analysis (DMA). The pendulum hardness, pencil hardness and flexibility were also tested. The results showed that the synthesized PUAs had low volume shrinkage and excellent adhesion in glass, PC and PVC substrates.     

Generalized corresponding states correlation for self-diffusion coefficients of fluids

The simple principle of corresponding states may be generalized to include substances that depart from strict conformality by introducing state dependent shape factors. This approach is applied to self-diffusion coefficient using a modified Enskog dense gas theory. Results are obtained for both saturated liquids and supercritical fluids and are generally within experimental error.     

Various properties of diimide–diacid-modified saturated polysters

Polyesterdiimide prepolymers containing synthesized diimide–diacid monomer (DIDAn) were synthesized under conditions previously under conditions previously reported. One-component varnishes were obtained by mixing the synthesized prepolymers with phenol-blocked toluene diisocyanate (TDI) and/or hexamethylene diisocyanate (HMDI). The solubility parameter of diimidemodified polyester prepolymer was investigated using an intrinsic viscosity measurement. Thermal behavior and pyrolysis activation energy were also investigated using thermogravimetric analysis. The thermal stability increased with an increase in the content of DIDA. The diimide-modified polyester one-component varnishes coated onto an aluminum panel were found to be acceptable, according to the specification of ASTM D-3794. © 1994 John Wiley & Sons, Inc.     

High temperature mechanical properties of zirconia metastable t'-Phase degraded yttria stabilized zirconia

Air plasma sprayed (APS) 8 wt%-yttria stabilized zirconia (8YSZ) with metastable tetragonal prime phase (t′) has been widely applied as thermal barrier coatings (TBCs) for gas turbine blades because of its outstanding mechanical properties at high temperatures. In the present research, a carefully designed process was used to prepare 8YSZ samples with different phase composition (t′, t and c) simulating the phase degradation of the material during operation conditions. High temperature (1000–1200 °C) bending strength, elastic modulus, and thermal expansion coefficient were measured, which exhibit strong dependence on the phase degradation during heat treatment. Effect of the phase composition on high temperature thermo-mechanical properties and the enhancement of the bending strength have been discussed, providing a new perspective for further improvements.     

磷酸二氢钾结晶介稳区性质研究

在磷酸二氢钾的生产中,为得到理想的晶体粒度及其分布,要求结晶在磷酸二氢钾水溶液的介稳区内进行,因此研究了不同温度、不同降温速率及不同搅拌速度下磷酸二氢钾水溶液的介稳区宽度,同时研究了铁离子杂质对磷酸二氢钾水溶液介稳区宽度的影响.结果表明:温度升高,介稳区宽度变窄;降温速率增大,介稳区宽度变宽;搅拌速度增大,介稳区宽度变窄,低温区变化幅度为2 ℃左右,高温区变化幅度小于1 ℃;铁离子的存在使介稳区宽度变宽,并得到介稳区宽度与铁离子质量分数的定量关系.     

合成橡胶常压氢化及产物性能

简介了合成橡胶的３种常压氢化方法：（１）用水溶性Ｗｉｌｋｉｎｓｏｎ催化剂在常压氢下使合成胶所合成胸乳在常压与氢化。指出第３种方法最有发展前景,用此方法除了可制备氢化度高的丁腈胶乳外,不可制备具有热塑性弹性体性质的氢化丁苯胶乳及氢化聚丁二烯胶乳;最后二者不经硫化即可用于制备老化的浸渍制品、涂料、粘接剂、复合垫片等。     

含钛有机硅树脂改性端羟基饱和聚酯的合成及性能

通过缩聚反应,用含钛有机硅预聚体对端羟基饱和聚酯树脂进行化学改性,用傅里叶变换红外光谱对改性聚酯树脂的结构进行了表征.以封闭型聚异氰酸酯为固化剂将其固化成膜,检测了涂膜的物理机械性能、耐热性以及耐蚀性.结果表明,改性后的聚酯具有良好的物理机械性能,按质量比1:1改性后的聚酯树脂其耐热、耐蚀性能显著提高,开始分解温度从改...