Polylactide films formed by immersion precipitation: Effects of additives,nonsolvent, and temperature

The influence of nonsolvent, crystallinity of the polymer film, and addition of dodecane (a poor solvent for the polymer and for the nonsolvent) on the morphology of polylactides films has been investigated and was related to phase separation behavior. Both amorphous poly‐DL ‐lactide (PDLLA) and crystalline poly‐L ‐lactide (PLLA) were dissolved in dichloromethane, and subsequently films were made by immersion in nonsolvent baths. PDLLA gave dense films without any internal structure, since the structure was not solidified by crystallization or glassification. PLLA films show varying structure depending on the nonsolvent. With methanol, asymmetric morphologies were observed as a result from combined liquid‐liquid demixing and crystallization, while with water symmetric spherulitic structures were formed. As a next step, dodecane was added, which is not miscible with the nonsolvent, and we found it to have a strong influence on the morphology of the films. The PDLLA films with dodecane did not collapse: a closed cell structure was obtained. In PLLA films, dodecane speeds up phase separation and induces faster crystallization in the films, and the porosity, size of the pores, and interconnectivity increased. When the PLLA solutions were subjected to a heat pretreatment, crystallization could be postponed, which yielded a cellular structure around dodecane, which did not contain spherulites anymore. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 959–971, 2007     

反相微乳液法制备高溶度ZrO2陶瓷墨水(Ⅰ)

尝试采用新颖的反相微乳液法制备陶瓷墨水，为了获得高溶度陶瓷墨水，对反相微乳液体系优选进行研究，着重就Triton x-100/醇／烷／水体系，采用目测法，分光光度法，电导率法和离心分离法，分别考察了不同醇，烷配伍时体系的稳定性和相关物理性质，根据这些性质是否突变以确定体系是否发生相变，给出了体系拟三元相图。实验表明，在20℃时Triton x-100／正己醇／环己烷／水反相微乳液体系表现优异，当Triton x-100与正醇的质量比为3：2时达到最大范围的反相微乳液区，最大溶水量时的最佳组成为Triton x-100:正己醇：环己烷：水＝19．1％：12．8％：23．7％：44．4％（质量比）。     

Thermodynamic assessment of MCl–YCl3 (M=Na,K, Rb,Cs) systems

Thermodynamic properties and phase diagrams of the MCl–YCl₃ (M=Na, K, Rb, Cs) systems were reassessed by using the CALPHAD method with the latest phase diagram data. A two-sublattice ionic solution model (M⁺)_P(Cl⁻, ${\mathrm{YCL}}_6^{3-}$, YCl₃)_Q reflecting the ionic behavior of the components was adopted to describe the liquid phase in the systems. A new set of optimized model parameters was found, and the calculated phase diagrams and enthalpies of mixing have good agreement with experimental data. The calculated liquidus near to YCl₃ side agrees much better with experimental data compared with previous work. In consideration of high and low temperature modifications as well as stability of intermediate compounds, Gibbs energies of formation of these compounds evaluated in the present work are more reasonable.     

Experimental investigations and thermodynamic modelling of KCl–LiCl–UCl3 system

Experimental investigations and Gibbs energy modelling of KCl–LiCl–UCl₃ system employing CALPHAD method are reported. Gibbs energy modelling of the subsystems KCl–UCl₃ and LiCl–UCl₃ was carried out primarily using phase diagram data from the literature. For the Gibbs energy modelling of the KCl–LiCl subsystem, new phase boundary data corresponding to four terminal compositions $(x_{\mathrm{LiCl}}=0.03$, 0.05, 0.95 and 0.97) obtained through differential thermal analysis data along with thermochemical and phase diagram data from the literature were used. Thermal analysis was also carried out for KCl–LiCl eutectic mixture containing small amounts of UCl₃ $(x_{{\mathrm{UCl}}_3}=9.03\times {10}^{-3}$ and $1.79\times {10}^{-2}$). The liquidus temperatures for these compositions were found to be 637 K and 674 K. Electromotive force data for dilute solutions of UCl₃ in the KCl–LiCl eutectic melt, measured in the temperature range 708–833 K in the present work, were found to be in good agreement with the literature data. These data were also used as input for the Gibbs energy modelling of the KCl–LiCl–UCl₃ system. In order to improve the quality of the resulting Gibbs energy functions of the quasibinaries and the quasiternary, enthalpies of mixing of the corresponding melts estimated using an empirical correlation based on surrounded-ion model were also used as input. Finally, the generated Gibbs energy functions were used to compute phase equilibria.     

控制图在复极电解槽控制中的应用

根据离子膜制碱工艺的特点，与控制图的应用理论相结合，寻找控制对象并选择控制图的类型。通过选择合适的工艺参数，使用控制图的数据处理技术对实际数据进行处理，绘制出控制图，利用参数波动符合正态分布的特点对控制图的波动情况进行分析，用来诊断电解槽运行的受控情况。     

Cr^3＋=Al2（WO4）3晶体生长助熔剂体系的研究

本文用DTA和XRD法研究了Na_2O-Al_2O_3-WO_3三元系中的Al_2(WO_4)_3-Na_2WO_4截面的相平衡关系。在这截面中发现一新化合物AlNa_3(WO_4)_2。以45mol％Na_2WO_4为助熔剂生长了Cr~(3+):Al_2(WO_4)_3晶体。     

Phase Diagram for Liquid Crystalline Polymer/ Polycarbonate Blends

A novel mechanism to form binary polymer blends is through phase separation by spinodal decomposition in the unstable region of the phase diagram. The present work investigates the effects of thermally‐induced phase separation by spinodal decomposition on the morphology development of liquid crystalline polymer/polycarbonate blends. Moreover, a thermodynamic binary phase diagram is obtained using a twin‐screw extruder at various processing melt temperatures. Differential scanning calorimetry and scanning electron microscopy were used to study the miscibility of the blends and the resulting morphology. A thermodynamic binary phase diagram exhibiting a lower critical solution temperature was obtained. The droplet size distribution of the blend was also obtained and discussed in light of the Cahn‐Hilliard theory.     

Characterization of dilute and dense phase vertical upflow gas-solid transport based on average concentration and velocity data

Dilute, ‘dense phase 1’, and possibly a third regime-‘dense phase 2’, were observed in a vertical 0.02 m diameter pneumatic conveyor using 210 μm sand particles. The transitions were marked by the alterations in the trend of the measured average solids hold-up while varying the solids mass flowrate at constant air velocity. Hydrodynamic characteristics together with the transition criteria for the various transport modes were established. A novel regime diagram based on average gas velocities and solids mass flowrates was developed to identify the operating conditions for these regimes, as well as the limiting solids carrying capacities of the present conveyor. A probable cause of the dilute to dense phase transition is speculated upon.     

反相微乳液法制备陶瓷彩喷墨水(Ⅰ)

系统地研究了Span80-Tween60/助乳化剂/油/FeCl3反相微乳液体系。通过正交实验,进行方差分析,得出最佳反相微乳液体系。通过均匀实验和全面实验,绘制出体系的拟三元相图,并由相图得出体系的最佳比例。绘制出最大溶水量与温度的曲线,从而确定最佳乳化温度。在最佳温度、最佳比例下,配制出两种墨水,并测定了墨水的表面张力、粘度、电导率和稳定性等性能。     

助乳化剂对化妆品乳液稳定性和液晶性的影响

以硬脂酸蔗糖酯和失水山梨醇硬脂酸酯的复配物（SSE）为主乳化剂，十六／十八醇及甘油为助乳化剂制备含液晶乳液化妆品。通过观察乳液的温度稳定性和液晶性，用三元相图研究助乳化剂含量对此乳液体系液区的影响。实验条件下，用该乳化剂体系可获得较好的液晶化妆品乳液，总之，较高的助乳化剂量有利于乳液的温度稳定性和液晶性，但助乳化剂量较低时经合理配方也能获得稳定的液晶乳液，其中含3％高碳醇和5％甘油的乳液稳定性及液晶性均较好，5％高碳醇和3％甘油的助乳化剂体系不宜采用。