无皂乳液聚合制备SiO_2/PMMA纳米复合胶体微球

采用半连续无皂乳液聚合方法在未经硅烷偶联剂改性的230 nm亲水性SiO2微球表面聚合甲基丙烯酸甲酯(PMMA)壳层,制备以SiO2粒子为核、PMMA为壳层的复合胶体微球。研究微球表面形貌、组成、粒径变化规律,探索聚合反应的成核过程和PMMA进料流量对复合微球粒径的影响。结果表明,在未经硅烷偶联剂改性的纳米SiO2表面可形成稳定规整的PMMA壳层,SiO2/PMMA复合胶体微球球型度接近1.0,单分散性较好,多分散度指数(PDI)小于0.04。聚合反应受甲基丙烯酸甲酯(PMMA)单体含量控制,随着PMMA进料流量增加,乳胶粒子成核过程由均相成核过渡为胶束成核,复合微球粒径加速增大,多分散性增强,其粒径可通过调节PMMA进料流量控制。     

HDI板盲埋孔填胶量化分析及模型探索

文章定量分析了半固化片对盲埋孔填胶的影响因素,在此基础上,正交分析确定了盲埋孔填胶的主要控制因素（填胶深度和PP片数量）,为前端工程设计和控制提供依据。最后,建立盲埋孔填胶的胶体流动模型,即在层流状态下的渗流模型,服从达西定律。     

Molecular exchange in thermal equilibrium between dissolved and crystalline tripalmitin by NMR

An NMR technique to measure exchange kinetics at thermal equilibrium in dispersions of moderately soluble crystalline material is presented. By monitoring the exchange of molecules between pools in solid and dissolved form, one can characterize the surface specific exchange rate. Illustrative experiments were performed in a model system with β-type crystals of tripalmitin as the solid phase and tripalmitin, a fraction of it deuterated, dissolved in a medium-chain TG oil as the liquid phase. The concentration of deuterated tripalmitin in the solvent was followed by ²H NMR after the crystals, which initially lack deuterated tripalmitin, were immersed in the liquid. The variation of the ²H concentration in the solvent provided the surface specific exchange rate. No systematic errors, due to the slight difference in properties of the deuterated tripalmitin compared to hydrogenated tripalmitin, were observed. The methodology worked well between crystal concentrations of 2 and 4 wt%.     

Interactions between laponite and microbial biofilms in porous media: implications for colloid transport and biofilm stability

Quartz sand columns and sand-filled microscope flow cells were used to investigate the transport characteristics of the clay colloid laponite, and a biofilm-forming bacterium, Pseudomonas aeruginosa SG81. Separate experiments were performed with each particle to determine their individual transport characteristics in clean sand columns. In a second set of experiments, bacterial biofilms were formed prior to introduction of the clay colloids. In the independent transport experiments, bacteria and laponite each conformed to known physicochemical principles. A sodium chloride concentration of 7 x 10(-2) M caused complete retention of the laponite within the sand columns. P. aeruginosa SG81 was generally less influenced by ionic strength effects; it showed relatively low mobility at all ionic strengths tested and some (albeit reduced) mobility when introduced to the columns in 1M NaCl, the highest concentration tested, but nevertheless showed reproducible trends. Under conditions favourable to laponite retention and biofilm stability (7 x 10(-2) MNaCl), laponite suspensions were able to remobilise a portion of the attached bacterial biomass. At low ionic strength, the profile of laponite elution was also altered in the presence of a P. aeruginosa biofilm. These observations suggest that while a reduction in ionic strength has a dominant influence on the mobilisation of biological and inorganic colloids, the presence of laponite and biomass can have a distinct influence on the mobility of both types of colloids. Since these events are likely to occur in subsurface environments, our results suggest that colloid-biofilm interactions will have implications for colloid-bound contaminant transport and the remobilisation of pathogens.     

An atomic force microscope study of calcium carbonate adhesion to desalination process equipment: effect of anti-scale agent

Whilst carbon dioxide is water soluble the system is somewhat complex and results in the presence of carbonate anions which interact with cations such as Ca²⁺ and Mg²⁺ present in seawater to form insoluble carbonates, especially at high temperatures. In multistage flash (MSF) desalination plants CO₂ gas becomes less soluble in the brine as a result of the brines high temperature and high salinity which causes the pH to be in the range of 8–9. The presence of these conditions causes the release of CO₂, simultaneous to the formation of scale deposits since its solubility is a function of the solution pH.

The formation of scale deposits, such as CaCO₃ causes fouling in the MSF distillers which has previously been studied by many researchers. A great amount of work has been carried out and more is yet to come in order to fully understand the role of various components and their interaction including the effectiveness of scale control techniques. The deposits may serve as an adsorbing film raising the speed of the loss of crystals or promoting the formation of scale deposits and therefore further adhesion on the wall surfaces of the MSF distillers and other process plant equipment leading to deterioration in the performance and efficiency of the whole desalination plant.

This paper shows direct quantification of the adhesion forces between CaCO₃ crystals and different process equipment surfaces under different conditions. This was carried out using an atomic force microscope (AFM) with an attached CaCO₃ crystal as a colloid probe to bring the CaCO₃ directly into and out of contact with the surfaces and measuring the resultant adhesion. This involved using surfaces different grades of roughness and carrying out measurements in synthetic sea water solutions of differing ionic strengths as well as with real seawater samples. Furthermore, the effect on measured adhesion of adding anti-scalant to the solutions was examined.     

无皂乳液聚合制备三维有序聚合物大孔材料

采用氨催化水解正硅酸乙酯制备了单分散二氧化硅微球,通过透射电子显微镜观察微球的粒径及其单分散性。利用垂直沉积法制备二氧化硅胶体晶体,通过扫描电子显微镜观察其形貌,利用紫外-可见光分光光度计对其带隙结构进行表征。结合模板技术,采用无皂乳液聚合制得三维有序聚苯乙烯大孔材料,通过扫描电子显微镜观察结构的有序度。结果表明:聚苯乙烯大孔材料结构高度有序,形成开放的三维通道网络,为聚合物大孔材料在诸多领域的潜在应用提供了可能。     

The Elimination of Channeling and Foam Overturning in Continuous Mode Adsorbing Colloid Flotation with a Sodium Dodecylsulfate/Dodecanoic Acid Mixture

Abstract

The effect of hydraulic loading, surfactant concentration, and air flow rate on the removal of Cr(III), Ni(II), and Zn(II) from chromium stream electroplating wastewater by adsorbing colloid flotation using a sodium dodecylsulfate/dodecanoic acid mixture was investigated. Typically, heavy metal concentrations of 81 ppm Cr(III), 55 ppm Ni(II), and 3.3 ppm Zn(II) were reduced to 1.2 ppm Cr(III), 3.2 ppm Ni(II), and 0.05 ppm Zn(II) at a hydraulic loading of 22.9 m³/m²·h (3 L·min^?1), an air flow rate of 45.8 m³/m²·h (6 L·min^?1), 40 ppm dodecanoic acid, and 80 ppm sodium dodecylsulfate, and using a 10-cm inner diameter column. A novel mode of operation (high liquid carryover) was used whereby a large proportion of the liquid entering the column leaves the column with the foam.     

从IC封装产品可靠性谈封装冲切模具优化设计

随着电子产品市场日益升温,电子产品朝超薄、超小等方向发展,产品量的需求越来越大,产品可靠性越来越高,塑料封装模具的冲切工艺产生的分层现象是影响产品可靠性的主要原因之一。文章首先叙述了冲切过程产生的分层情况,其次从模具结构方面说明冲切产生分层的原因,并针对产生分层的原因提出冲切模具的优化设计,最后总结从实际生产过程中防分层要求设计冲切模具和框架,可避免在实际生产过程中IC胶体分层导致产品可靠性问题。     

四组分组成及性质对煤焦油沥青质初始絮凝点的影响

为保障煤焦油悬浮床加氢装置的稳定操作,需对原料的沥青质絮凝现象及影响因素进行研究。研究了煤焦油沥青质初始絮凝点测定方法、四组分组成性质及重油分子结构参数对煤焦油中沥青质絮凝现象的影响。以一种高温焦油A、一种中低温焦油（大于320 ℃重油）B和两者混合油C为试样,采用光度计法测量焦油样品A、B、C的沥青质初始絮凝点。将煤焦油样品分离为饱和分、芳香分、胶质和沥青质四个组分,采用元素分析、相对分子质量测定、核磁共振H谱等分析手段,对样品性质和平均分子结构进行表征。结果表明,三种焦油样品均有不同程度的沥青质絮凝情况,其胶体稳定性为：A>B>C。四组分组成和性质共同决定样品的胶体稳定性。A样品因为具有高度缩合的稠环芳烃,侧链短且少,m(胶质)/m(沥青质)比值大,各组分芳香度、相对分子质量等性质连续分布,所以沥青质在芳香分和胶质中的分散情况较好,体系相对最稳定。A、B样品组成和性质差异大,导致二者不能很好相溶,因此混合焦油C样品胶体稳定性差。     

Platinum colloid catalyzed etchingless gold electroless plating with strong adhesion to polymers

Echingless electroless plating (ELP) process that can produce gold thin film with strong adhesion to various polymer films has been developed. We have found that platinum (Pt) colloidal nanoparticles have excellent catalytic activity for ELP. The Pt colloidal nanoparticles can be immobilized via electrostatic interactions on a substrate simply by dipping it into a Pt colloid. Owing to the excellent catalytic property of the Pt nanoparticles, continuous gold thin films can be produced at room temperature using a simple cyanide-free gold electroless plating solution composed of chloroauric acid and hydrogen peroxide. The process requires no surface modifications for the immobilization of the catalyst, and by simple post-annealing the adhesion of the plated films to various polymer films can be improved by three orders of magnitude in comparison to that of “as-deposited” film. The process developed in this work is expected to be an environment-friendly thin metal film deposition process without the use of toxic and hazardous substances.