高性能纳米涂料的表面原位纳米改性制备方法

本发明公开于一种高性能纳米涂料的表面原位纳米改性制备方法，它是利用湿化学制备纳米粉体的技术，在常规涂料制备的过程中加入纳米粉体的先驱物，反应控制剂和稀释剂等，直接在颜料填料微粒的表面原位合成相应的纳米粉体，并通过这些纳米粉体定向亲和性的匹配控制使它们附聚在颜填料颗粒的表面上并形成相应的定向排列状态。其步骤分为纳米粉体先驱液的制备和纳米涂料的制备两步，本发明可以制备具有显著纳米改性效果的高性能纳米涂料。

21世纪——在改性中拓展空间的PP包装材料(续完)

另外,PP润湿张力kN/m为31,相容性为8.1,耐疲劳弯曲可达10万次,脆性温度为-35℃,氧气渗透性1.50,吸水率为0.005以下,水蒸气透率0.6g/m^2hr/mm,收缩率较大,香味非透过性稍不良好,紫外线(366nm)透过性大,油的非渗透性良好,除气体不透过性,热粘连性,非带电性较差。影响包装质量另一大因素是透明性。

Synthesis of 4,4＇-MDC in the Presence of Sulfonic Acid-functionalized Ionic Liquids

The synthesis of methylene diphenyl dimethylcarbamate （4,4＇-MDC） from methyl N-phenyl carbonate （MPC） and formaldehyde （HCHO） was conducted in the presence of sulfonic acid-functionalized ionic liquids （ILs） as dual solvent-catalyst. The influences of the kind of anion in the ionic liquids, reaction conditions and the recycle of the ionic liquid on 4,4＇-MDC synthesis reaction were investigated. In addition, the acid strength of ILs was de-termined by the Hammett method with UV-visible spectroscopy, and the acid strength-catalytic activity relationship was correlated. The activity estimation results showed that [HSO3-bmim]CF3SO3 was the optimal dual solvent-catalyst. Under the suitable reaction conditions of 70℃, 40 min, molar ratio of nMPC/nHCHO= 10/1 and mass ratio of WILs/WMPC = 4.5/1, the yield of 4,4＇-MDC based on HCHO was 89.9 % and the selectivity of 4,4＇-MDC with respect to MPC was 74.9%. Besides, [HSO3-bmim]CF3SO3 was reused four times after being purified and no significant loss in the catalytic activity was observed.

Zinc leaching from electric arc furnace dust in alkaline medium

Physical and chemical properties of electric arc furnace （EAF） dust from Tianjin seamless Pipe Company were measured and analyzed. The zinc leaching tests in alkaline medium were carried out under variation of leaching agent concentration, leaching temperature, leaching cumulative time and solid-to-liquid ratio. The thermodynamics and kinetics of the zinc leaching process were also analyzed. The results show that the EAF dust contains 10% （mass fraction） zinc and the median particle size is 0.69 μm. The zinc recovery of 73.4% is obtained tinder the condition of 90 ℃, 6 mol/L NaOH, and 60 min leaching time. With the increase of concentration of NaOH and the cumulative time, zinc leaching will be significantly increased. The kinetics study demonstrates that the leaching reaction is chemically controlled and the reaction activation energy is 15.73 kJ/mol.

Pre-activation based stereoselective glycosylations: Stereochemical control by additives and solvent

Stereochemical control is an important issue in carbohydrate synthesis.Glycosyl donors with participating acyl protective groups on 2-O have been shown to give 1,2-trans glycosides reliably under the pre-activation based reaction condition.In this work,the effects of additives and reaction solvents on stereoselectivity were examined using donors without participating protective groups on 2-O.While several triflate salt additives did not have major effects,the amount of AgOTf was found to significantly impact the reaction outcome.Excess AgOTf led to lower stereochemical control presumably due to its coordination with the glycosyl triflate intermediate and a more SN1 like reaction pathway.In contrast,the stereoselectivity could be directed by reaction solvents,with diethyl ether favoring the formation of glycosides and dichloromethane leading to β isomers.The trend of stereochemical dependence on reaction solvent was applicable to a variety of building blocks including the selective formation of β-mannosides.

Electric-field control of the activity of the graphene-based catalyst

Effects of an electric field on CO oxidation of Au-embedded graphene are investigated using first-principles method. Results of our calculations show that the initial step of the reaction is more likely to proceed via the Langmuir-Hinshelwood mechanism in the presence of the field, and the reaction barrier can be tuned continuously by the electric field. However, the applied electric field makes it more difficult for the product of the reaction, CO2, to desorb from the reaction site. These two competing effects make an electric field not entirely advantageous in controlling the activity of Au-embedded graphene for CO oxidation reaction. Nevertheless, the findings of our study provide a basis for further investigation on control of chemical reactions by electric fields.

Diffusion-controlled synthesis of Cu-based catalysts for the Rochow reaction

The properties of materials are strongly dependent on their structures. The diffusion effect is a main kinetic factor that can be used to regulate the growth and structure of materials. In this work, we developed a systematic and feasible strategy to synthesize Cu2O solid spheres and hexahedrons by controlling the diffusion coefficients. These Cu2O products can be successively transformed into corresponding Cu hollow spheres and hexahedrons as well as CuO porous spheres and hexahedrons by controlling hydrogen diffusion in hydrazine hydrate solution and controlling oxygen diffusion in air, respectively. The formation of these transformations was also discussed in detail. Tested for Rochow reaction, the as-prepared Cu2O solid and CuO porous spheres exhibit higher dimethyldichlorosilane selectivity and Si conversion than Cu hollow spheres, which is attributed to the active sites for CH3Cl adsorption formed in CuxSi phase after the removal of oxygen atoms in Cn2O and CuO in the formation of dimethylchlorosilane. The present work not only develops a feasible method for preparing well shape-defined Cu2O solid spheres and hexahedrons but also clarifies the respective roles of Cu, Cu2O and CuO in dimethyldichlorosilane synthesis via Rochow reaction.