Slot coating flows of non‐colloidal particle suspensions

Slot coating is used in the manufacturing of functional films, which rely on specific particle microstructure to achieve the desired performance. Final structure on the coated film is strongly dependent on the suspension flow during the deposition of the coating liquid and on the subsequent drying process. Fundamental understanding on how particles are distributed in the coated layer enables optimization of the process and quality of the produced films. The complex coating flow leads to shear‐induced particle migration and non‐uniform particle distribution. We study slot coating flow of non‐colloidal suspensions by solving the mass and momentum conservation equations coupled with a particle transport equation using the Galerkin/Finite element method. The results show that particle distribution in the coating bead and in the coated layer is non‐uniform and is strongly dependent on the imposed flow rate (wet thickness). © 2016 American Institute of Chemical Engineers AIChE J, 63: 1122–1131, 2017     

圆盘反应器液膜表面更新数值模拟

以圆盘反应器的开发和放大为背景,通过理论分析将液膜更新频率与液膜变形相关联,运用VOF模型研究竖直旋转圆盘液膜更新频率空间分布特性;将量纲分析与数值模拟相结合考察影响普通圆盘液膜平均更新频率的相关因素;从表面更新的角度研究自由膜与附壁膜的差异,优化圆盘结构。结果表明:圆盘表面液膜加速区液膜更新频率最快,较其他区域高150%,较平均值高75%;获得了普通圆盘液膜平均更新频率表达式;圆盘开窗形成自由膜,更新频率比附壁膜高40%以上;相同面积圆形窗区域自由膜更新频率比扇形窗自由膜高34%,但是扇形窗自由膜对附壁膜强化作用更明显。     

溶胶—凝胶陶瓷薄膜制备工艺技术的研究

本文从溶胶制备和薄膜涂覆工艺两方面对溶胶－凝胶法制备陶瓷薄膜中的工艺技术进行了研究,并指出了溶胶－凝胶技术中存在的一些问题。     

游离TDI和薄膜蒸发

降低聚氨酯涂料中游离TDI最有效的方法是采用薄膜蒸发器,文章对其结构、原理及其国内生产厂均作了简要叙述。     

柔性ITO导电薄膜制作技术

主要介绍了柔性ITO导电薄膜的工艺技术参数及生产加工流程。     

活性锆白颜料研究与应用

综述了用化学镀膜工艺制备的Zr-0l、Zr-02型活性锆白颜料是一种用途极其广泛的氧化锆型颜料,又称活性锆白粉.活性锆白颜料的制备,使粉体具有多种功能：耐候性、耐蚀性、悬浮性、疏水性,在卷钢涂料和汽车涂料上已成功应用.并指出今后方向和发展趋势.     

Coupled fluid‐particle modeling of a slot die coating system

This work seeks to develop a fundamental understanding of particle motion in the slot die coating process through studying the interaction of forces between particles, with the die walls and the fluid phase. Coupled computational fluid dynamics and the discrete element method is employed for evaluating the motion of individual suspended particles near moving surfaces in a complex three‐dimensional flow field, motivated by the flow of particle laden fluid in a slot die coating system, including the presence of free surfaces. Overall, the particles follow the flow streamlines and their final position in the coating depends on the initial entry region of the particles. Particles experiencing adhesion with each other agglomerate in the low velocity regions of the coating gap, and have long residence times near the edge of the die at the end of the feed slot in the coating gap. © 2016 American Institute of Chemical Engineers AIChE J, 62: 1933–1939, 2016     

Hydrophobic hybrid inorganic-organic thin film prepared by sol-gel process for glass protection and strengthening applications

Hybrid systems based on 3-trimethoxysilyl propyl methacrylate, tetramethylorthosilicate, and methyl methacrylate were developed for moisture protection and strengthening of glass objects. The hydrophobic behavior of the hybrid was obtained by adding different fluorinated precursors to the hybrid solution. Experimental results show that among different fluorinated percursors, 1H,1H,2H,2H-perfluorooctyl trichlorosilane gives the best results, increasing the water contact angle up to 100° and decreasing the free surface energy. Coated glasses exhibit higher strength (more than 50%) than uncoated glasses. The strengthening was interpreted in terms of a healing mechanism. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 2387–2393, 1997     

Numerical Study of Solid-Liquid Two-Phase Flow in StirredTanks with Rushton Impeller(Ⅱ) Prediction of Critical Impeller Speed

The critical impeller speed, NJS, for complete suspension of solid particles in the agitated solid-liquid two-phase system in baffled stirred tanks with a standard Rushton impeller is predicted using the computational procedure proposed in Part I. Three different numerical criteria are tested for determining the critical solid suspension. The predicted NJS is compared with those obtained from several empirical correlations. It is suggested the most reasonable criterion for determining the complete suspension of solid particles is the positive sign of simulated axial velocity of solid phase at the location where the solid particles are most difficult to be suspended.     

搅拌槽内液-固两相体系的数值研究(Ⅱ)临界搅拌转速的预测

The critical impeller speed, NJS, for complete suspension of solid particles in the agitated solid-liquid two-phase system in baffled stirred tanks with a standard Rushton impeller is predicted using the computational procedure proposed in Part Ⅰ. Three different numerical criteria are tested for determining the critical solid suspension. The predicted NJS is compared with those obtained from several empirical correlations. It is suggested the most reasonable criterion for determining the complete suspension of solid particles is the positive sign of simulated axial velocity of solid phase at the location where the solid particles are most difficult to be suspended.     

透明导电氧化物镀膜玻璃在光伏电池中的应用

详细阐述了透明导电氧化物(TCO)镀膜玻璃的技术特点和性能特性,研究了镀膜玻璃各指标参数对于光伏电池模块的影响及变化程度,对比分析了不同生产方式和种类的TC0镀膜玻璃在光伏应用上的优劣特性和改进方向.为开发新型TCO镀膜玻璃和不断提高光伏电池性能打下了一定的理论基础.     

功能表面材料与流体界面相互作用对垂直降液膜流动特性的影响

通过调节水温度、添加表面活性剂以及铝合金壁面表面改性处理来改变降膜流体与固体表面之间的表面自由能差值,运用JDC-2000型精密测微仪测定垂直降液膜的厚度,研究固体表面和液体间相互作用对流体垂直降膜流动特性的影响;考察了液膜雷诺数、流体温度、添加表面活性剂、固体表面材料物理化学性质等因素对垂直壁面降液膜流动特性的影响规律。实验结果表明:改变固体表面与降液膜流体的物理化学特性,即改变固液界面的相互作用能够改变流体的降膜流动特性。降液膜平均厚度随液固表面自由能差的增大而减小。     

功能氧化物薄膜液相沉积制备及应用研究进展

回顾了液相沉积表面涂覆方法的历史起源。重点阐述了液相沉积方法制备具有光催化活性和紫外光诱导下的双亲性的TiO2薄膜材料的制备工艺,在光催化反应、自清洁材料、抗菌、防腐、防垢等领域的应用研究进展。提出了深化液相沉积微观机理研究,制备增强光催化活性和扩大可接收太阳辐射范围的功能薄膜,开发节能防垢等多功能表面以及从循环经济角度研究液相沉积过程等进一步研究的方向。     

镜像流体法模拟单颗粒沉降和绕凸起物流动

提出一种新的计算流体力学方法,即镜像流体法,通过指定固体区域内的流场参数,使相界面边界条件隐含满足,使得固液两相运动可以在固定的欧拉坐标系中求解。采用SIMPLE算法和控制容积法离散控制微分方程组。利用镜像流体方法数值模拟了单个球形颗粒的自由沉降过程,以及幂律流体、Carreau-Bird流体和粘弹性的Oldroyd-B流体绕半圆环形、三角形和梯形凸起物的二维圆管流动问题,模拟结果与报道的实验数据及计算结果很接近,初步验证了本算法的可靠性。     

涂料用固体丙烯酸树脂的悬浮聚合研究

本文系统考察了悬浮聚合中影响涂料用固体丙烯酸树脂分子量及其分布的各种因素;对丙烯酸酯的悬浮二元共聚及加入第三组分共聚进行了研究,考察了不同单体对产物的影响;并且探讨了悬浮聚合的稳定性和粒径大小的影响因素,确定了合成涂料用固体丙烯酸酯较好的工艺条件。     

Evolution of surface chemistry and physical properties during thin film polymerization of thermotropic liquid crystalline polymers

By applying a novel thin film polymerization technique, X-ray photoelectron spectroscopy (XPS), and the Lifshitz-van der Waals acid-base (LWAB) theory, we have determined the time evolution of surface chemistry and surface free energy during the polymerization of liquid crystalline poly(p-oxybenzoate/2,6-oxynaphthoate) at a molar ratio of 50/50. The surface free energy components of these main-chain liquid crystalline copolyesters were calculated from contact angle measurements using a Ramé-Hart goniometer and a three-liquid procedure (water, glycerol, and diiodomethane). The experimental data suggest that the Lewis base parameter (y-) during thin film polymerization decreases rapidly with the progress of polymerization, while the Lewis acid parameter (γ⁺) and the Lifshitz-van der Waals parameter (γ^LW) are almost invariant. The surface roughness data measured by atomic force microscopy (AFM) suggested that the increase in water contact angle (or the decrease in y-) was not caused by the change in surface roughness, but by the change in surface chemistry, i.e. due to the reaction of acetoxy and carboxy groups to release acetic acid during the polymerization reaction. In addition, the XPS results coincide with our previous Fourier transform infrared spectroscopy results showing that the condensation polymerization is much faster in the beginning than in the later stages. Consequently, the decrease in y- in the early stages of the polymerization is well explained.     

Effect of excess Li2S on electrochemical properties of amorphous li3ps4 films synthesized by pulsed laser deposition

Amorphous Li₃PS₄ films were synthesized by pulsed laser deposition (PLD) at room temperature using Li₃PS₄ targets with excess lithium and sulfur. Raman and X‐ray photoemission spectroscopies indicated that the Li₃PS₄ film synthesized with a stoichiometric amount of Li₃PS₄ target contained lithium‐deficient phases such as Li₄P₂S₆, Li_2?xS and sulfur due to composition deviation caused during the ablation process. The film synthesized with a 14% Li₂S‐excess target (Li_3.42PS_4.21) contained fewer impurities, and exhibited a higher ionic conductivity of 5.3 × 10^?4 S/cm at 298 K than the lithium‐deficient film (3.1 × 10^?4 S/cm). The target composition is an important factor for the fabrication of highly conductive Li₃PS₄ films for electrolytes in thin‐film batteries.