The mesh disturbance effects in a low‐temperature cascade arc torch for surface modification of low density polyethylene

A stainless steel mesh was placed in a low‐temperature cascade arc torch (LTCAT) to study its disturbance effects on the plasmas and on the surface modification of low density polyethylene (LDPE). It was found that the photoemitting species were deflected by the screen and only faint glow was observed after the mesh. Optical emission spectroscopy examination indicated that the amount of electronically excited species in the plasma was greatly reduced after passing through the mesh. Grounding the mesh altered the nature of the discharge and a greater intensity of O emission was observed in Ar LTCAT + O₂ discharge, which indicated greater energy transfer to the oxygen. Although a decrease in surface damage was observed on the treated LDPE samples by placement of the mesh in the Ar LTCAT discharges, the wettability achieved was also greatly reduced. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Flame versus air atmospheric gliding arc plasma treatment of polypropylene-based automotive bumpers: Physicochemical characterization and investigation of coating properties

In this research, the polypropylene (PP) sheets used for automotive bumper surface were treated using two methods: air atmospheric gliding arc plasma and flame modifications. Atomic force microscopy was applied to study the morphology of surfaces before and after treatment processes. While calculating the surface free energy (SFE), contact angle of the surfaces was measured, and the chemical composition of the PP surface was analyzed using X-ray photoelectron spectroscopy. Surface modifications by gliding arc plasma increased the ratio of the oxygen and nitrogen atoms on the surface by 100%, indicating that polar chemical functionalities form on the surface. The surface morphology was highly affected by gliding arc plasma treatments, which triggered an impact on roughness and etching. It was also found that the SFE was drastically increased by certain modifications. Noticeable improvement was also observed in wettability by the gliding arc plasma technique. In the next stage, polyurethane paints were coated on the treated and untreated PP surfaces. Then, we examined the flame and gliding arc plasma treatments' effect on coating properties of PP bumper, adhesion analysis, water immersion resistance, and sulfuric acid resistance. Finally, high-pressure carwash test and gloss analysis were conducted on the treated and untreated coated sheets, respectively.     

从国家危险废物标准角度思考硫酸厂酸性废水处理技术

介绍了硫酸厂含砷、镉危险固体废物的可能来源,并详细分析了石灰法、石灰-铁盐法、硫化法加石灰-铁盐法等酸性废水处理技术的特点和存在问题。从国家危险废物标准角度提出改进硫化法加石灰-铁盐法设计,采用间歇式反应器替代连续式反应器进行硫化反应。处理后废水中ρ（As）平均2．25mg／L、除砷效率99．96％到接近100％,ρ（Cd）平均7．77mg／L、除镉效率93．63％-99．36％;产生的硫化物渣中的砷、镉可回收利用,含铁盐石膏渣中砷、镉等有害物质含量低于GB5085．6—2007标准规定限值,可直接用作建筑材料。