浮选法分离废旧ABS和PS–HI中pH值的影响

在对比甲醇与乙酸浮选分离丙烯腈–丁二烯–苯乙烯塑料(ABS)和高抗冲聚苯乙烯(PS–HI)的基础上,研究了乙酸、氢氧化钠、盐酸调节单宁酸–松油醇–水体系的pH值对ABS和PS–HI浮选的影响,并通过测量接触角对吸附机理进行了分析。实验结果表明,pH值会改变废旧ABS,PS–HI的亲/疏水性;要达到最佳分离效率,最适pH值在酸性范围内;不同pH调节剂对ABS,PS–HI的亲/疏水性影响不同,用乙酸调节pH值时PS–HI的疏水性变化较小,最适pH值为3~4;用盐酸调节pH值时ABS的亲水性基本保持不变,最适pH值为4~5.5。吸附机理表明,H+在单宁酸和塑料之间起桥梁作用,且H+对ABS的抑制性更强。     

表面活性剂处理浮选分离ABS和PC塑料的研究

研究了聚碳酸酯(PC)和丙烯腈-丁二烯-苯乙烯(ABS)两种密度相近的塑料在非离子表面活性剂仲醇聚氧乙烯醚(Tergitol 15-S-7)存在下的可浮性。通过调节表面活性剂浓度、起泡剂浓度以及浮选时间等因素,最终表面活性剂浓度60 mg/L、起泡剂浓度10 mg/L、浮选时间40 min时,ABS/PC混合塑料体系的浮选分离效果最佳,ABS的纯度和回收率接近100%,PC的纯度达到72.34%。实验结果表明,表面活性剂处理选浮分离有利于塑料的回收利用。     

金属丝网超亲/疏水性强化气液相界面运动

利用多孔结构进行液体的导流和气液分离是近年来强化传热的研究热点,主要原理是气液固三相界面的受力平衡,固相材料的亲疏水性则是决定微孔内气液固三相界面运动规律的关键因素。针对具有一定亲水性的金属铜网,进行超亲水和超疏水处理;考察多孔结构亲疏水性对相界面以及气液两相分离效果的影响。结果表明,金属铜网具有浸润自相容性;经过亲疏水表面改性后,超亲水性能阻挡气泡的通过;超疏水性能的多孔铜网更易与气体为伍,形成致密气封膜,阻挡液体进犯。静态实验测定多孔丝网的浸润自相容能力,接触角为151°丝网,对液相阻滞力为117.6N·m^-2;接触角为0°的超亲水丝网对气相阻滞力为49N·m^-2,并建立了多孔结构浸润自相容性与分离临界气泡尺寸的数学关联。     

金属丝网超亲/疏水性强化气液相界面运动

利用多孔结构进行液体的导流和气液分离是近年来强化传热的研究热点,主要原理是气液固三相界面的受力平衡,固相材料的亲疏水性则是决定微孔内气液固三相界面运动规律的关键因素。针对具有一定亲水性的金属铜网,进行超亲水和超疏水处理;考察多孔结构亲疏水性对相界面以及气液两相分离效果的影响。结果表明,金属铜网具有浸润自相容性;经过亲疏水表面改性后,超亲水性能阻挡气泡的通过;超疏水性能的多孔铜网更易与气体为伍,形成致密气封膜,阻挡液体进犯。静态实验测定多孔丝网的浸润自相容能力,接触角为151°丝网,对液相阻滞力为117.6 N·m~(-2);接触角为0°的超亲水丝网对气相阻滞力为49 N·m~(-2),并建立了多孔结构浸润自相容性与分离临界气泡尺寸的数学关联。     

有机颜料的HLB值计算

有机颜料与表面活性剂同为有机化合物,它们的化学结构式都由疏水基团(非极性基团)和亲水基团(极性基团)所组成.它们的HLB计算值可由已确定的有机性值(疏水性)和无机性值(亲水性)加和后,通过简单计算而得知.     

环氧树脂涂层表面亲水性对微藻黏附性能的影响

在固体材料表面黏附成膜是微藻细胞的一种生理特性。近些年基于微藻生物膜的生物过程,如生物膜贴壁培养和防附着技术受到了很多关注。微藻在固体材料表面的黏附受藻细胞与材料表面之间的相互作用的影响,建立黏附强度与材料表面性质参数间的关系对于通过材料选择来强化或控制微藻生物膜具有非常重要的意义。本工作的目的是揭示和明确材料亲疏水性对微藻黏附的影响,提出了一种双酚A环氧(EP)树脂表面亲疏水改性的方法。通过将亲水性的二乙醇胺(DEA)或疏水性的聚甲基聚硅氧烷(PMHS)加入到EP树脂中反应,EP树脂表面水接触角在36.80?~98.34?范围内可通过加入不同量的DEA或PMHS实现任意可调,材料的表面水接触角与DEA或PMHS加入量之间有线性关系。重要的是这种改性方法获得的材料,其形貌、结构、表面粗糙度等表面性质几乎没有变化,从而在研究和关联微藻黏附量与材料表面亲疏水性(表面水接触角)之间的关系时可以排除亲疏水性之外的其他表面性质的影响;其次,考察了小球藻和栅藻在不同亲疏水性材料表面的黏附行为,结果表明小球藻和栅藻在亲水性和疏水性材料表面均能黏附成膜,但在亲水性材料表面黏附更多更快;建立了微藻最大黏附容量与材料表面接触角之间关联关系,表明微藻最大黏附容量随材料表面水接触角的增大而线性降低,栅藻的表面黏附容量比小球藻大。     

环氧树脂涂层表面亲水性对微藻黏附性能的影响（英文）

在固体材料表面黏附成膜是微藻细胞的一种生理特性。近些年基于微藻生物膜的生物过程,如生物膜贴壁培养和防附着技术受到了很多关注。微藻在固体材料表面的黏附受藻细胞与材料表面之间的相互作用的影响,建立黏附强度与材料表面性质参数间的关系对于通过材料选择来强化或控制微藻生物膜具有非常重要的意义。本工作的目的是揭示和明确材料亲疏水性对微藻黏附的影响,提出了一种双酚A环氧(EP)树脂表面亲疏水改性的方法。通过将亲水性的二乙醇胺(DEA)或疏水性的聚甲基聚硅氧烷(PMHS)加入到EP树脂中反应,EP树脂表面水接触角在36.80°～98.34°范围内可通过加入不同量的DEA或PMHS实现任意可调,材料的表面水接触角与DEA或PMHS加入量之间有线性关系。重要的是这种改性方法获得的材料,其形貌、结构、表面粗糙度等表面性质几乎没有变化,从而在研究和关联微藻黏附量与材料表面亲疏水性(表面水接触角)之间的关系时可以排除亲疏水性之外的其他表面性质的影响;其次,考察了小球藻和栅藻在不同亲疏水性材料表面的黏附行为,结果表明小球藻和栅藻在亲水性和疏水性材料表面均能黏附成膜,但在亲水性材料表面黏附更多更快;建立了微藻最大黏附容量与材料表面接触角之间关联关系,表明微藻最大黏附容量随材料表面水接触角的增大而线性降低,栅藻的表面黏附容量比小球藻大。     

日本研制出塑料涂装用仿金属水性涂料

日本近日研制出一种塑料涂装用仿金属水性涂料，该涂料由聚合物水分散体树脂、金属颜料和着色颜料、成膜助剂、水性涂料用助剂和水组成，可用于各种塑料表面的涂装，特别适用于ABS，PS，HIPS，PC／ABS，ABS／PS，PS／PP，POM，PAM，PVC塑料的表面涂装。     

日研制出塑料涂装用仿金属水性涂料

日本最近研制出一种塑料涂装用仿金属水性涂料．该涂料由聚合物水分散体树脂、金属颜料和着色颜料、成膜助剂、水性涂料用助剂和水组成．可用于各种塑料表面的涂装，特别适用于ABS、PS、HIPS、PC／ABS、ABS／PS、PS／PP、POM、PAM、PVC塑料的表面涂装。     

溶气浮选法分离废旧ABS / PS塑料

以分离废旧ABS/PS塑料为目标,在实验室特制的溶气浮选柱中考查了润湿剂、起泡剂、调整时间、浮选时间等因素对废旧塑料浮选行为的影响,获得了最佳浮选分离工艺条件。实验表明,采用溶气浮选技术,以单宁酸为润湿剂,在其浓度25mg/L,起泡剂松油醇浓度5mg/L、调整时间15min、浮选时间15min的条件下,可以成功地实现废旧ABS和PS塑料的浮选分离,上浮产物PS的纯度90.12%,回收率97.45%,下沉产物ABS的纯度97.24%,回收率89.38%。研究结果同时表明,要有效地克服混合塑料给浮选过程带来的不利影响,塑料颗粒间相互作用的系统研究将是该领域的重要课题。     

Floatability and desulfurization of a low-rank (Turkish) coal by low-temperature heat treatment

It is well known that higher rank coals are inherently hydrophobic whereas lower rank coals are more hydrophilic. Because of the hydrophilic character of low-rank coals, they are difficult to float even at high dosages of oily collectors. In the present study, the floatability behavior of a hydrophilic lignitic coal was investigated with and without low-temperature heat treatment using a column flotation and a Denver flotation cell. The floatability and hydrophobicity of the coal were investigated upon heating the coal at 105 °C. After heating it was found that the floatability, hydrophobicity, and separation efficiency of lignite increased dramatically. A change in the hydrophobicity of lignite before and after the low-temperature heating was determined by FTIR spectroscopy. On the other hand, reverse flotation experiments applied in natural, alkaline, and acidic conditions yielded rather good results. A concentrate assaying 1.52% total sulfur was obtained at natural pH from a feed of 2.50% sulfur.     

废旧冰箱混合塑料静电分选关键参数影响研究

采用废旧冰箱整体破碎分选得到的混合塑料破碎料作为原料，利用自由落体式静电分离机进行处理后得到丙烯腈?丁二烯?苯乙烯共聚物（ABS）、高抗冲聚苯乙烯（PS?HI）两种废塑料破碎料，通过缺口冲击强度、拉伸强度、分选效率等测试研究了原料预处理与静电分离机工艺等多个关键参数对分选效果的影响。结果表明，控制较低的混合塑料破碎料含水率可以明显提高静电分选的效率和产物性能；静电分选场电压在27 kV 时，喂料速度在550 r/min 时可以达到最佳的分选效率和产物性能；静电分离机极间距在200 和220 mm 左右时可以分别达到ABS 和PS?HI 的最佳分选效率和力学性能。     

Chemical modification of polyethersulfone nanofiltration membranes: A review

Polysulfone (PS) and poly(ether)sulfone (PES) are often used for synthesis of nanofiltration membranes, due to their chemical, thermal, and mechanical stability. The disadvantage for applying PS/PES is their high hydrophobicity, which increases membrane fouling. To optimize the performance of PS/PES nanofiltration membranes, membranes can be modified. An increase in membrane hydrophilicity is a good method to improve membrane performance. This article reviews chemical (and physicochemical) modification methods applied to increase the hydrophilicity of PS/PES nanofiltration membranes. Modification of poly(ether)sulfone membranes in view of increasing hydrophilicity can be carried out in several ways. Physical or chemical membrane modification processes after formation of the membrane create more hydrophilic surfaces. Such modification processes are (1) graft polymerization that chemically attaches hydrophilic monomers to the membrane surface; (2) plasma treatment, that introduces different functional groups to the membrane surface; and (3) physical preadsorption of hydrophilic components to the membrane surface. Surfactant modification, self‐assembly of hydrophilic nanoparticles and membrane nitrification are also such membrane modification processes. Another approach is based on modification of polymers before membrane formation. This bulk modification implies the modification of membrane materials before membrane synthesis of the incorporation of hydrophilic additives in the membrane matrix during membrane synthesis. Sulfonation, carboxylation, and nitration are such techniques. To conclude, polymer blending also results in membranes with improved surface characteristics. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Ageing of plasma-treated poly(tetrafluoroethylene) surfaces

Highly hydrophobic poly(tetrafluoroethylene) (PTFE) surfaces were modified with an air glow discharge plasma to improve their wettability. However, the hydrophilic character obtained diminishes with time, due to molecular movement in the polymer. We have determined that the ageing process is strongly affected by the environment and temperature in which the surfaces are stored. A hydrophobic environment and high temperatures promote faster recovery of the original properties of PTFE than low temperatures. Nonetheless, a hydrophilic environment, even at high temperatures, prevents the surface from losing the polar character obtained from the plasma treatment, stopping the ageing process. Moreover, this process is reversible since the character of the treated surface changes when the environment changes (i.e. from water to air). The hydrophilicity of the surfaces was evaluated by contact angle measurements of a droplet of water.     

Adsorption of Proteins and Cell Adhesion to Plasma Treated Polymer Substrates

Plasma treatment is often used to alter cell interaction with polymer surfaces used in biomedical application. The influence of surface hydrophilicity/hydrophobicity on human mammary epithelial cell (HMEC) proliferation and adhesion of protein albumin to plasma treated polystyrene (PS) was studied. The PS surface was made hydrophilic or hydrophobic by treatment either in O₂ or CF₄ plasma. The rate of protein adhesion was studied by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) after incubation of PS in albumin solution for different periods, while cell viability and morphology was studied by MTT assay and scanning electron microscope (SEM). XPS measurements have shown that the quantity of adsorbed protein was higher for both plasma treated samples than for the untreated one. No significant difference regarding protein adhesion on hydrophilic or hydrophobic plasma treated surface was found by XPS. Contrary, the results for cell proliferation showed much better proliferation on hydrophilic surface.     

Separation of Polyvinyl Chloride from Plastic Mixture by Froth Flotation after Surface Modification with Ozone

Selective modification by ozonation for the surface of polyvinyl chloride (PVC) was evaluated to separate PVC from the other plastics, polyethylene terephthalate (PET), polycarbonate (PC) and polymethyl methacrylate (PMMA), with almost the same density as PVC by the froth flotation process. Ozonation could selectively decrease the contact angles of flexible PVC from 87.5 degrees to 68.4 degrees and rigid PVC from 90.3 degrees to 66.9 degrees, whereas little decreases in the contact angle were observed for other plastics. This would be due to the replacement of the chloride group on the surface of PVC, into hydrophilic functional groups; carbonyl, carboxyl and ester group. The PVC was successfully separated from the other plastics by the froth flotation process after the selective surface modification by ozonation.     

废旧混合塑料识别分离与清洗技术研究进展

针对废旧混合塑料工业化回收循环利用过程中分类识别和高效清洗两大关键技术难题,本文主要综述了系列可工业用废旧混合塑料分类识别方法;讨论了浮沉分离、浮选分离、电选分离、近红外光谱精准识别技术在废旧塑料识别中的应用;介绍了清洗工艺除污提高分离效果的重要性和清洗剂主要成分——碱性物质、助剂和表面活性剂以及其作用;并提出了将超声波清洗以及浮沉分离、浮选分离、近红外光谱识别分离用于废旧塑料精准识别与分离的集成技术工艺路线。由于国内近红外光谱识别技术与超声波清洗技术相对落后,指出研究此两项技术、设备并将两者结合应用于废旧塑料回收是今后的发展方向。     

电化学法强化高硫煤浮选脱硫试验研究

研究了电解还原法和金属腐蚀电偶法对煤和黄铁矿表面改性的机理。应用红外光谱和X射线衍射分析可知，煤和煤系黄铁矿经不同电化学法预处理后，表面性能向相反的方向改性，有利于两者的浮选分离。在一定的电化学条件，黄铁矿表面生成亲水性的物质，可浮性降低，煤表面的含氧官能团减少，疏水性增强。大量研究结果表明；电化学强化高硫煤浮选脱硫方法能有效脱除精煤中的硫分，提高产品质量。