复合型导电塑料的研究进展

介绍了复合型导电塑料的种类。特性与应用，讨论了它们的导电机理及影响导电性的因素。着重全叙述了国内外对添加抗静电剂、导电填料以及共混复合型导电塑料的研究现状与发展趋势。     

Effect of filler network on dynamic viscoelastic properties of uncured polymethylvinylsiloxanes filled with silica and carbon black

Dynamic properties of polymethylvinylsiloxane (PMVS) filled with filler‐blends composed of carbon black (CB) and silica (SiO₂) were investigated using an advanced rheometric expansion system. A variety of weight fraction of CB to SiO₂ were 0/100, 10/90, 30/70, 50/50, 70/30, 90/10, and 100/0, and a bifunctional organsilane, bis(3‐triethoxysilylpropyl)tetrasurfane, was used to facilitate the filler dispersion. The results reveal that the incorporation of CB/SiO₂ filler‐blends into PMVS result in a reduced Payne effect. This effect reaches a minimum when the ratio of CB/SiO₂ approaches 1, and then it began to rebound with the ratio increase. Meanwhile, a characteristic Newtonian viscosity plateau appearing in low frequencies also significantly decreases, depending on the amount of CB or SiO₂ added. On the basis of a simplified Fowke model, we ascribe this phenomenon to the deteriorated filler network, which is predominantly induced by the totally different surface activity between CB and SiO₂. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3477–3482, 2006     

填料对双组分缩合型室温硫化硅橡胶性能的影响

考察了多种补强填料和半补强(或增量)填料如硅藻土、碳酸钙和氧化铝等对室温硫化(RTV)硅橡胶的机械性能和介电性能的影响。结果表明,采用经六甲基二硅氮烷处理的气相法白炭黑或沉淀法白炭黑作填料时,RTV硅橡胶多方面的性能都有所提高;采用补强填料和半补强填料并用的RTV硅橡胶的性能优于使用单一补强填料的RTV硅橡胶;随着填料用量的增加,RTV硅橡胶的机械性能、相对介电常数和介质损耗因数都有一定程度的提高,但体积电阻率有所降低。     

GaN基LED与Si键合技术的研究

采用金属键合技术结合激光剥离技术将GaN基LED从蓝宝石衬底成功转移到Si衬底上。利用X射线光电子谱(XPS)研究不同阻挡层对Au向GaN扩散所起的阻挡作用,确定键合所需的金属过渡层。利用多层金属过渡层,在真空、温度400℃和加压300 N下实现GaN基LED和Si的键合,通过激光剥离技术将蓝宝石衬底从键合结构上剥离下来,形成GaN基LED/金属层/Si结构。用金相显微镜及原子力显微镜(AFM)观察结构的表面形貌,测得表面粗糙度(RMS)为12.1 nm。X射线衍射(XRD)和Raman测试结果表明,衬底转移后,GaN基LED的结构及其晶体质量没有发生明显变化,而且GaN与蓝宝石衬底间的压应力得到了释放,使得Si衬底上GaN基LED的电致发光(EL)波长发生红移现象。     

桂柳高速公路两侧土壤重金属分布特征

选择桂柳高速公路上的4个调查剖面和1个对照剖面测试了公路两侧农田土壤中Pb、Cd、Cr、Hg和As的含量分布。结果表明,公路交通对路两侧土壤重金属含量有一定的影响,运行期较长的对照路段桂黄公路两侧土壤中的Pb、Cd和As的含量明显高于运营期较短的桂柳高速公路段,而Cr、Hg与公路运行期长短的关系不是非常密切;重金属含量在横向上都有随距路肩距离的减小而增大的趋势,Pb、Cd在路肩两侧200m范围内含量的变化较小。以广西水稻土土壤背景值为评级标准,采用单因子指数法评价了路侧土壤的环境质量：所测路段和剖面的Cd、Hg污染均较严重;Cr基本上还处在非污染水平;桂黄公路段Pb的污染指数高于高速公路段。     

脱硫灰与石灰石粉复合制备沥青填料研究

通过XRD及马歇尔稳定度试验等方法,研究把脱硫灰用作沥青复合填料。试验结果表明,以不大于40%的脱硫灰与石灰石粉复合可制备沥青填料,所制备的沥青混合料各项指标均能满足规范要求,可应用于沥青道路工程,其中以约30%脱硫灰取代石灰石粉所制备的复合沥青填料效果较好。     

Sulfur-Tolerant NOx Storage Traps: An Infrared and Thermodynamic Study of the Reactions of Alkali and Alkaline-Earth Metal Sulfates

The sulfur tolerance of a barium-containing NO_x storage/reduction trap was investigated using infrared analysis. It was confirmed that barium carbonate could be replaced by barium sulfate by reaction with low concentrations of sulfur dioxide (50 ppm) in the presence of large concentrations of carbon dioxide (10%) at temperatures up to 700 °C. These sulfates could at least be partially removed by switching to hydrogen-rich conditions at elevated temperatures. Thermodynamic calculations were used to evaluate the effects of gas composition and temperature on the various reactions of barium sulfate and carbonate under oxidizing and reducing conditions. These calculations clearly showed that if, under a hydrogen-rich atmosphere, carbon dioxide is included as a reactant and barium carbonate as a product then barium sulfate can be removed by reaction with carbon dioxide at a much lower temperature than is possible by decomposition to barium oxide. It was also found that if hydrogen sulfide was included as a product of decomposition of barium sulfate instead of sulfur dioxide then the temperature of reaction could be significantly lowered. Similar calculations were conducted using a selection of other alkaline-earth and alkali metals. In this case calculations were simulated in a gas mixture containing carbon monoxide, hydrogen and carbon dioxide with partial pressures similar to those encountered in real exhausts during switches to rich conditions. The results indicated that there are metals such as lithium and strontium with less stable sulfates than barium, which may also possess sufficient NO_x storage capacity to give sulfur-tolerant NO_x traps.     

乳胶涂料中填料粒径测定与分散剂的选择

介绍了重力沉降法和容量沉降法两种测定乳胶涂料中填料粒径的方法。通过比较粉体粒径结果显示：沉降法比激光法更形象直观，更能代表体系粒径真实情况。以滑石粉、重钙、轻钙粉体为基准，采用不同用量、不同类型的分散剂的容量沉降法进行比较得出：用容量沉降法能定量地对分散剂性能做出评价。     

The use of wood pulp and radiation‐modified starch in wastewater treatment

Radiation‐induced graft copolymerization of maize starch/acrylic acid has been performed. Also, natural byproduct wood pulp was used after chemical treatment for the removal of metal ions from the investigated wastewater. The surface and structure morphology of the wood pulp and starch/acrylic acid were investigated by scanning electron microscopy and infrared spectroscopy. The physical parameters, such as swelling, gel percentage, and grafting efficiency (%) of starch/acrylic acid copolymer, were studied. The factors affecting the abilities of the prepared materials for removing heavy metal ions and dyes from aqueous solutions were studied. It was found that the maximum metal uptake is in the following sequence: Fe³⁺ > Cr³⁺ > Pb²⁺ > Cd²⁺. The adsorption capacity of such investigated metal ions increases with the increase of pH values. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

粉煤灰作橡胶填料的影响因素

以钛酸酯偶联剂为表面处理荆，对粉煤灰进行表面处理，制得橡胶填料，测试了该填料对橡胶的补强作用。实验表明，表面改性后的粉煤灰对橡胶具有较好的补强作用。可完全替代碳酸钙、碳酸镁或陶土，产生较好的补强效果，用来替代部分发黑，可以减少发黑的用量，降低橡胶的成本。