An original concept for the synthesis of an oxide coating: The film boiling process

The film boiling chemical vapor process is an original and rapid synthesis method for ceramic coatings and composites. This work reports the deposition of silica coating from tetraethyl orthosilicate (TEOS) by film boiling chemical vapor process. Experiments were carried out under atmospheric pressure between 900 °C and 1100 °C. Several modifications of the experimental setup were made in order to allow a better thermal monitoring. Silica coatings were fast synthetized: several microns per minute. An activation energy of 209 kJ/mol ± 20 was deduced. The structure and microstructure of the oxide coating were characterized by Optical Microscopy, Scanning Electron Microscopy, Energy Dispersive Spectroscopy, Electron Probe MicroAnalyzer, Fourier-Transform InfraRed spectrometery and X-ray diffraction.     

Biofunctional calcium titanate coating on titanium by simple chemical treatment process using calcium-hydroxide slurry—Effects of the heating temperatures

The present study investigates the effect of the heating temperature on the characteristics of the surface layer in a simple treatment process using calcium-hydroxide slurry. Furthermore, biofunctions of the treated titanium surfaces, such as bioactivity in a simulated body fluid and corrosion resistance under a bio-environment, are also investigated. Our treatment process using calcium-hydroxide slurry is as follows: a titanium substrate is buried in calcium hydroxide slurry, and the slurry is then heated in air. The calcium hydroxide slurry was prepared by mixing of calcium hydroxide powder and water. When treated at heating temperature beyond 873 K, a crystallized calcium titanate coating is formed on a titanium substrate and further, the thickness increases with the increase of heating temperature. On the crystallized calcium titanate coating, calcium phosphate is precipitated in a simulated body fluid; therefore, the treated titanium surface has bioactivity. Furthermore, anodic current density of the treated surface is 10–10³ times lower than that of the non-treated surface.     

Analysis of a liquid‐assisted molding process for coating microchannels with an ultraviolet curable polymer

Injection molding can be altered to form hollow parts by partially pre‐filling a mold with polymer melt and then injecting a gas into the mold before cooling. The gas will core the center section and in the process force melt into the unfilled portions of the mold. This process is called gas‐assisted injection molding (GAIM) and is a thoroughly studied polymer processing technique. Liquid‐assisted molding follows the same principles as GAIM, except the coring fluid is a liquid of low viscosity. Liquid‐assisted molding of an ultraviolet (UV) curable polymer can be used to coat microchannels, the benefit of which being a smooth and circular cross‐section. Presented here are experiments of the controlled microchannel flow of a long, immiscible liquid thread through a viscous UV curable polymer. The roles of channel geometry and bubble velocity are discussed for square, rectangular, and circular microchannels. Finally, a quasi‐analytical model for calculating the Newtonian coating fluid thickness, when the coring fluid is driven by a constant pressure, was developed using the equation for Poiseuille‐like flow within a square channel. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

Comparative performance of an adiabatic and a nonadiabatic PSA process for bulk gas separation—a numerical simulation

A detailed numerical model of a Skarstrom‐like PSA process is used to investigate the separation performance of an adiabatic and a nonadiabatic process for removal of bulk CO₂ impurity from inert He. The complexity of the gas phase adsorbate composition, adsorbate loading, and the adsorbent temperature profiles as functions of positions inside an adsorber at the start and end of each step of the PSA process are discussed. The separation performance of a nonadiabatic PSA process is generally inferior to that of the corresponding adiabatic process. Smaller adsorbent column diameter accentuates nonadiabatic operation and hence lower separation efficiency. Furthermore, the separation efficiency decreases more rapidly at short cycle times and smaller column diameters. Insulation of PSA columns of a process development unit operated under these conditions is recommended for reliable data analysis. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4066–4078, 2017     

Adjustable amine–epoxy composition in a stratified thin film with a spin‐coating process: A useful tool for establishing relationships between the local glass‐transition temperature at the interface and the network structure

An easy method for preparing supported homogeneous epoxy–amine thin films on a silica surface consisting of two distinct layers was developed via spin coating from epoxy–amine solutions. Because of these two layers had the controlled properties of the upper layer, we showed that it was possible to precisely control the epoxy–amine stoichiometry in the sublayer through the initial epoxy–amine ratio, the spin‐cast process, and the overall film thickness. First, in the thin films, the primary amine–epoxy conversion was constant, whatever the thickness and initial epoxy–amine stoichiometry for a given curing schedule. As the primary amine conversion can be independently tuned in thin films, it thus provided a rather unique and easy method for better understanding the relationship between the network structure curing at the interface and the resulting properties, such as the glass‐transition temperature (T_g) and elastic modulus. Here, we also showed that we could access the local T_g; this implied a potential application of these experimental data in predictive composite material properties. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42078.     

溴化丁基橡胶/聚酰胺动态硫化热塑性弹性体的性能与应用研究

采用溴化丁基(BIIR)和聚酰胺(PA)为主要原材料,通过动态硫化技术制备了BIIR/ PA热塑性弹性体(TPV),TEM和AFM测试结果显示TPV分散相BIIR的粒径在0.5至5μm之间。采取挤出吹膜方法试制成功了TPV薄膜,测定分析了TPV薄膜的阻隔性能、拉伸性能、伸张疲劳性能及耐热空气老化性能,结果表明其各项性能优良,阻隔性能突出,特别适合用于轮胎气密层和要求高阻隔性的软管等的生产。。进行了薄膜用于轮胎气密层的应用研究,制备了TPV薄膜与过渡层的复合胶片,利用该复合胶片作为气密层部件进行轮胎试制,解决了TPV薄膜与胎体复合时存气、皱褶的工艺难题。试制的轮胎通过GB/T 4502-2016标准中的高速性能、耐久性和低气压性能等,轮胎减重5%以上。