摩擦带电涂装工艺用改性环氧树脂

本发明阐述了三个方面的内容：①适合摩擦带电涂装工艺用的改性环氧树脂；②为获得合适的摩擦带电性[即能够摩擦带电]，在粉末涂料组合物中使用本发明的环氧树脂；③阐述了含有聚酯树脂和本发明环氧树脂的粉末涂料组合物。     

影响摩擦枪粉末涂料带电量的因素探析

通过理论结合试验的方法,探讨了粉末涂料在摩擦喷涂过程中,影响摩擦带电量的各种因素。研究了摩擦助剂、粉末粒径、粉末类型、气压大小对带电性能以及工件上粉率的影响。     

合理内外衣穿着减少服装摩擦带电量：常用衣料带电序列的实验研究

通过对市售常有的２４种衣料的摩擦带电实验，排列出相互间的带电序列，为记电服时合理选用部分辅料，为操作人员合理内外衣，减少摩擦带电提供依据。     

空气输送可燃性粉体静电带电的防范

介绍了粉体带电的影响因素,从粒子与外用机械材料和粒子接触、摩擦、 分离时发生静电的现象,对带电原因进行了阐述。通过对空气输送粉体的除电、合成树 脂制品除电和浮游粉尘云的抑制方法,制订了静电带电防范有关措施。     

粉末涂料

200902046粉末涂料用树脂和助剂以及基于可再生资源的醇酸涂料；200902047低温固化涂料用氨基甲酸酯环氧化物的制备和应用；200902048坚韧熔结环氧粉末涂料及其制备方法；200902049摩擦带电粉末涂料；200902050纳米复合粉末涂料及其分散聚合制造方法；     

静电的危害与预防

静电并不是静止的电，是宏观上暂时停留在某处的电，是相对目前广泛使用的“流电”而言的。所谓静电是指绝缘物质上携带的相对静止的电荷，是由不同物体接触摩擦时，在物质间发生了电子转移而形成的带电现象。静电现象是人们最早发现的电现象，例如人们很早就发现用玻螭棒或琥珀与毛皮摩擦再分开时，前者就带了正电荷，后者就带负电荷。能够吸引或排斥羽毛、纸片和尘埃等轻小物体。这些电荷聚积于物体的表面上，不会象金属导体里的电流那样容易流动，因而称之为静电。那么，摩擦为什么能够产生静电，各种物态的物质又是怎样带上静电的，要回答这类问题，应当先作一些物质的微观分析。     

粉末静电喷涂工艺探讨

介绍了粉末的粒度组成与喷涂质量的关系,以及粉筛目数与孔径和粒径的对应关系.阐述了喷涂过程中粉末的带电过程与上粉率的问题.着重讨论了压缩空气温度、湿度的增大对涂层质量的影响.     

混杂纤维对摩擦材料性能影响的研究

本文采用腰果壳油、三聚氰胺改性粉末酚醛树脂为基体,陶瓷纤维、钛酸钾晶须和kevlar纤维混杂制备制动摩擦材料,研究了不同混杂纤维含量对摩擦材料摩擦磨损性能影响。结果表明,增强纤维含量过低或者过高均会导致摩擦材料摩擦性能的降低。陶瓷纤维、钛酸钾晶须和kevlar三种增强纤维混杂使用能够提高并稳定制动摩擦材料的摩擦系数,对降低摩擦材料的磨损率有明显的作用。推荐在纤维混杂摩擦材料配方中采用25％的纤维含量和3％的Kevlar纤维含量。     

高压电路防污闪带电清洗维护技术可行性研究

比较全面地论述了带电清洗中的高压带电清洗剂、高压带电清洗工具、高压带电施工工艺和高压带电安全措施等内容。     

芳纶在摩擦材料中的应用

本文介绍了芳纶在摩擦材料中的消费量,芳纶浆粕和芳烨粉末在聚四氯乙烯复合材料中的应用。     

Triboelectric charging of monodisperse particles in fluidized beds

To investigate the interplay between particle charging and hydrodynamics in fluidized beds, models for triboelectric charging and electrostatic forces were built into a computational fluid dynamics‐discrete element method model. Charge transfer was governed by the difference in effective work function between contacting materials as well as the electric field at the point of contact. Monodisperse particles were fluidized with an effective work function difference between the particles and the conducting walls. For smaller work function differences, hydrodynamics were not changed significantly as compared with an uncharged case. In these simulations, the average charge saturated at a value much lower than the value anticipated based on the work function difference, and a unimodal distribution of charges was observed. For larger work function differences, particles stuck to walls and bed height oscillations due to slugging were less pronounced. For these cases, a bimodal distribution of charges emerged due to effects from strong electric fields. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1872–1891, 2017     

Triboelectric Charging and Separation of Fine Powder Mixtures

For increasingly finer powders, the material-specific separation at high loadings is a challenging task, for instance in recycling processes. Here, a combination of triboelectric charging and electrostatic separation was investigated for powder mixtures of talcum and calcite. The dependencies of the triboelectric charge on the mass loading, the gas velocity, and the mixture ratio were investigated. While higher charge levels were achieved with increasing gas velocity, the mass loading had an opposite effect on the net charge. Although bipolar charge distributions were observed within pure materials and mixtures, electrical neutralization did not occur in the mixtures. Therefore, already in a non-optimized setup, a decent degree of material enrichment (of up to 53 %) was found on the separating electrodes.     

Control of electrical properties of polymers by chemical modification

This article reviews the use of chemical modification of preformed polymers as a means of tailoring their electrical properties. Specifically, triboelectric charging, photoconductivity and dark conductivity are considered.     

Influence of the Impaction Angle on the Triboelectric Charging of Aerosol Nanoparticles

A low pressure impactor is used to measure triboelectric charging behavior of metallic nanoparticles. Ag nanoparticles, produced by spark discharge, were impacted onto Pt sputtered targets. The influence of the impaction angle and impaction velocity on the triboelectric charging was investigated. While for perpendicular impaction the charge transfer behavior of previous work was confirmed, the oblique impaction revealed new phenomena. Additional charge transfer was observable, which increases with obliqueness. The possibility of mass transfer between particle and target due to the high-energy collisions was also investigated. SEM characterization and Auger spectroscopy indicate mass transfer from the particle to the target surface.     

Performance-Enhanced and Washable Triboelectric Air Filter Based on Polyvinylidene Fluoride/UiO-66 Composite Nanofiber Membrane

Applying triboelectric nanogenerators (TENGs) in air filtration systems to generate electric charges through friction is a major advancement in air cleaning technology. The performance of triboelectric air filter strongly depends on the properties of triboelectric materials. In this work, a better triboelectric material, polyvinylidene fluoride (PVDF)/UiO-66 composite nanofiber membrane (P6-NFM), is designed and fabricated through electrospinning technology by doping UiO-66 into PVDF matrix. As the weight ratio of UiO-66 increases to 1%, PVDF/UiO-66 composite nanofiber-based TENG (P6-TENG) achieves the maximum current, voltage, and triboelectric charge of 4.29 µA, 52.8 V, and 22.02 nC, which are 6.5 times, 5.1 times, and 8.0 times as large as those of pure PVDF-based TENG (P-TENG). Therefore, the triboelectric air filter based on P6-NFM can be easily charged by slapping the fiber membrane and spun-bond fabric. After charging, the removal efficiency of P6-NFM is 92% for PM_0.5 and 98% for PM_2.5, which are 2.8 and 1.2 times those of the uncharged one. More importantly, the filtration efficiency of this air filter keeps stable after the membrane is washed four times. This method of loading UiO-66 on the triboelectric fiber material shows tremendous potential in self-charging and reusable air purification applications.     

Electrostatically supported surface coating of solid particles in liquid nitrogen for use in Dry-Powder-Inhalers

The homogenous coating of particles in the micrometer range with fine-grained particles in the nanometer range leads to increasing flowability of the powder. Experiments have been carried out concerning the selective charging and coating of solid particles in liquid nitrogen. Liquid nitrogen as a suspension medium for solid particles offers certain advantages in comparison to other liquids and especially to gases. The charging of the fine-grained particles was realized by triboelectric charging as well as contact charging at metal electrodes at which a certain high voltage is applied. With selective charging of fine-grained solid particles, the coating quality of a powder mixture can be improved significantly. With respect to the use of coated particles in Dry-Powder-Inhalers (DPIs), the share of respirable particles reaching the lung is very high.     

Tribocharging of Three-Component Powder Mixtures

Adhesion of charged toner particles used in electrophotography is dominated by electrostatic forces. In this paper we discuss a model which describes the process by which toner particles acquire their electrostatic charge, tribocharging.

In previous papers, we have presented a model of tribocharging of two-component mixtures of powders based on the assumptions that:

1. The surface of each powder is populated with electron accepting and donating sites;
2. The density of states of the donating and accepting sites can be represented by narrow bands, all of which have the same energy; and
3. Charge is exchanged between donor and acceptor sites until thermodynamic equilibrium is established.

In this paper, we show how to extend this model to multi-component mixtures. The extended model can be used to calculate the charging behavior of three-component mixtures of electrophotographic toners and carriers based on measurements with two component mixtures. Experimentally-measured charging behavior agrees with the model predictions.

These results confirm it is possible to assign charging site densities to individual materials empirically. The site densities can then be used to predict charging behavior of the materials in mixtures which have not been studied experimentally. The success of the model also implies that toner particles migrate freely from carrier particle to carrier particle and that triboelectric interactions take place between toner particles of different compositions in mixtures.     

Improving the efficiency of coal triboelectric separation by chemical conditioning

A study of fine coal beneficiation in a laboratory triboelectric separation system was carried out to provide a fundamental understanding of improving the separation efficiency of thermal coal powder by chemical conditioning. Separation results of untreated and chemically treated fine coal were investigated. The experimental results demonstrated that the charge–mass ratios of clean coal and minerals increased greatly with ethanol serving as the modification chemical. The optimal deash efficiency of 85.46% was obtained when the coal was treated by 2.0 kg/t ethanol. However, excessive dosage of chemical agents had a bad effect on the separation results.     

Triboelectrification of particulate flows on surfaces: Part II — Mechanisms and models

Triboelectric charge accumulation both poses problems and offers opportunities for dry particulate processing. It generates hazards in many industrial systems, but is exploited in several important applications, including electrophotographic toner charging and triboelectric separation. However, the charging of continuous particulate flows on solid surfaces is poorly understood, and design of devices to optimise triboelectric behaviour is often qualitative or based on trial and error. This study attempts to identify the main charging mechanisms for a continuous particulate flow on a flat surface. The proposed charging models incorporate contact time, velocity and mode of contact. A model incorporating contact area effects arising from sliding and rolling contact is consistent with experimental data, as long as a charge limit is imposed on bouncing particles. A mechanism for this charge limit, involving separation discharge, is proposed. The effect of delocalised image charge on the system is estimated and found to be negligible. Some general design principles are proposed for triboelectric optimisation of particle processing devices.     

废旧塑料摩擦荷电机理及摩擦电选技术研究进展

塑料由于材质轻、化学性质稳定、成本低、耐磨性及耐腐蚀性好等优点被广泛应用于工程建设、食品安全、交通运输以及医疗等领域,如果处理不当会对环境造成严重的污染,废塑料污染防治已成为全球关注的环境问题。目前处理废旧塑料的常用方法有风选法、浮选法、静电分离法和光选法等,摩擦电选作为一种新型干式分选方法越来越受到研究者们的重视,其具有工艺简单、污染小、投资少、成本低等优点。本工作针对废旧塑料的分选回收利用,详细介绍了摩擦电选的荷电机理、影响因素、荷电装置和分选设备的研究现状,指出了目前通过摩擦电选回收废旧塑料的技术问题,并对摩擦电选技术未来的发展趋势和应用进行了展望。