光交联对HDPE凝胶量的影响

用安息香二甲醚和三(丙烯酰氧乙基)异氰尿酸酯(TAEIC)作为PE的光敏剂和助交联剂,研究了它们的用量、光照时间、交联温度,紫外光光强对PE交联度的影响。结果表明,安息香二甲醚是一种有效的光敏剂,引发效率较高;助交联剂可以提高交联效率;光照时间、紫外光光强和交联温度等对PE的交联度均有明显的影响。     

CAD中表格文档的计算机辅助实现方法的研究

产品CAD系统研究中，产品技术资料的处理通常以图形文档为主，但是，表格文档作为产品技术资料的重要组咸部分，在CAD作业中同样需要认真对待，特别是在电力变压器这类机电产品设计中表格文档所占比重比较大，显得尤为重要。本文对表格文档的组成形式、特点作了一些研究，并对CAD作业中表格文档的计算机辅助实现方法作了比较详细的介绍。     

叠片联轴器的振动特性及其影响因素分析

文中举例示出叠片联轴器的纵向和横向振动频率，着重分析比较了膜片数目，膜片宽度，中间轴和联轴器重量，螺栓所在处半径，垫片直径，膜片厚度和膜片组轴向位移对纵向和横向振动频率的影响及其影响程度，本文的计算结果对了解叠片联轴器的振动特性及其影响因素有重要的参考价值。     

Preparation and properties of phase‐change heat‐storage UV curable polyurethane acrylate coating

Phase‐change heat‐storage UV curable polyurethane acrylate (PUA) coating was prepared by applying microencapsulated phase change materials (microPCMs) to PUA coating. MicroPCMs containing paraffin core with melamine‐formaldehyde shell were synthesized by in situ polymerization. The effect of stirring speed, emulsification time, emulsifier amount, and core/shell mass ratio on particle size, morphology, and phase change properties of the microPCMs was studied by using laser particle size analyzer, Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopic analysis, scanning electron microscopy, and differential scanning calorimetry. The results showed that the diameter of the microcapsules decreased with the increase of stirring speed, emulsification time, and emulsifier amount. When the mass ratio of emulsifier to paraffin is 6%, microcapsules fabricated with a core/shell ratio of 75/25 have a compact surface and a mean particle size of 30 μm. The sample made under the above conditions has a higher efficiency of microencapsulation than other samples and was applied to PUA coating. The dispersion of microPCMs in coating and heat‐storage properties of the coating were investigated. The results illustrated that the phase‐change heat‐storage UV curable PUA coating can store energy and insulate heat. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41266.     

Synthesis of fluoroalkyl‐modified polyester and its application in improving the hydrophobicity and oleophobicity of cured polyester coatings

The fluoroalkyl‐modified polyester (PE‐F_n) was synthesized by the reaction of polyester resin (PE) and fluorinated isocyanate, and the structure of the synthesized product was characterized by proton nuclear magnetic resonance (¹H‐NMR) and fluorine nuclear magnetic resonance (¹⁹F‐NMR). The water and oil wettability of the cured PE coatings with PE‐F_n as additives was investigated by contact angle meter. The results showed that the introduction of an extremely low concentration of PE‐F_n into PE led to the increase in contact angle of water and diiodomethane on cured PE coatings, and the decrease in the surface free energy. The X‐ray photoelectron spectroscopic (XPS) analysis showed that the F/C molar ratio in the outer few nanometers was significantly higher than that in the bulk, indicating that the fluoroalkyl groups in PE‐F_n had enriched on the coating surface. It was also found that longer fluoroalkyl groups and fluoroalkyl groups with ? CF₃ at its end had the higher tendency to aggregate on the coating surface. The topological structures of the cured coatings were recorded by an atomic force microscope under tapping mode and the results revealed that there was a strong surface segregation of fluorinated species. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39812.     

陶瓷膜处理乙醇发酵废水的工艺条件研究

发酵法生产乙醇的过程中产生大量废水,文中采用陶瓷膜处理乙醇发酵废水,考察了膜孔径、料液性质以及操作条件对过滤过程的影响。结果表明,陶瓷膜过滤乙醇发酵废水有较好的效果,化学需氧量(COD)去除率达80%,固体悬浮物(SS)截留率在99%以上。确定了孔径为200nm的膜管在pH值为8.0,错流速度为5m/s,温度为50℃,操作压力0.15MPa条件下操作,膜通量大于700L/(m2·h)。     

邻苯二甲酸酐与环氧氯丙烷反应合成聚酯树脂

以四乙基溴化胺为催化剂,1,4-丁二醇为起始剂,邻苯二甲酸酐和环氧氯丙烷为原料合成聚酯树脂,采用傅立叶红外光谱(FT-IR)和核磁共振(1H-NMR)对产物的结构进行表征,并考察了催化剂用量和反应温度对合成聚酯树脂的影响.结果表明,合成聚酯树脂的端基为羟基,且随着温度升高和催化剂用量增加,反应速率增加,合适的反应条件为...     

Mechanism of the particle formation during the oxidative polymerization of 2,6‐dimethylphenol in an aqueous medium

The changes of the molecular weight and particle size with time during the oxidative polymerization of 2,6‐dimethylphenol in an aqueous medium were studied. At the beginning of the oxidative polymerization, the oligomers with the hydrophilic phenoxy anion at the end of oligomer chains are formed rapidly in the aqueous medium. When the molecular weight of the oligomer reaches up to a critical value, the oligomer precipitates out from the water, resulting in the formation of the original particle (or domain). With the increase of the molecular weight, the concentration of the phenoxy anion and the surface charge density of the original particles decrease; therefore, the repulsion force between original particles weaken and the stability of particles in water decreases, resulting in the coagulation of the original particle and the formation of the primary particle. With the further progression of the polymerization, the primary particles coagulate and final particles are formed. A three‐stage mechanism of the particle formation is proposed, that is, the particle nucleation, first coagulation, and second coagulation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3649–3653, 2007     

变速箱双层套环式组合密封结构有限元分析

利用ABAQUS建立变速箱双层套环式组合密封结构的二维轴对称模型,分析了密封圈的压缩量、介质压力对双层套环式组合密封结构的接触应力、变形、Von Mises应力分布的影响。结果表明:随着压缩量的增加,组合密封结构的变形及接触应力增大,V形橡胶圈的受力减小;随着介质压力的增加,组合密封结构的变形、接触应力及V形橡胶圈的受力增大,因此,在较大介质压力条件下,应适当增加压缩量;适当改变双层套环的尺寸,可以使V形橡胶圈受力减小,且齿形套环不易磨损,使用寿命延长。