Properties of poly(n‐butyl methacrylate) prepared by reverse atom transfer radical polymerization in an aqueous dispersed system

Reverse atom transfer radical polymerization (ATRP) of n‐butyl methacrylate (BMA) in waterborne media using Cu(II) complexes with azo initiators (i.e., reverse ATRP) was conducted. The influence of several factors, such as surfactant, catalyst, and reaction time, on the stability of the emulsion, the particle size, the morphology of the emulsion particles, and the control of the polymerization was investigated. The results showed great differences between ATRP and conventional emulsion polymerization, especially the nucleation mechanism and the kinetics. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1542–1547, 2003     

细胞激动素Kinetin合成的改进

介绍了用糠胺与腺嘌呤在催化条件下反应合成细胞激动素kinetin,该法原料易得,反应条件温和,产品收率及纯度都较高。     

气化炉复合炉衬的传热计算

新型 (多喷嘴对置 )水煤浆气化炉拟采用水冷管和耐火浇铸料组成的复合炉衬结构 .炉内的高温高压对复合炉衬的高温侵蚀十分严重 ,是影响其寿命的重要因素 ,因此合理设计气化炉复合炉衬的结构对充分发挥其材质的作用具有十分重要的意义 .建立了气化炉复合炉衬的传热计算的数学模型 ,同时编制了模型求解的计算程序 ,并用某工艺条件对复合炉衬的温度分布进行了计算 .结果表明 ,该方法可有效计算出复合炉衬的温度分布情况 ,为复合炉衬的设计、运行和维护提供理论依据     

In-situ studies of electron field emission of single carbon nanotubes inside the TEM

Electron field emission characteristics of individual multi-walled carbon nanotubes (MWCNTs) were investigated in situ inside the transmission electron microscope (TEM). For a single MWCNT it was found that while field-emission can hardly occur from the side of the nanotube, a curved nanotube may result in finite side emission and the best emission geometry is the top emission geometry. Current-voltage (I-V) measurements made at different vacuum conditions and voltage sweeps emphasize the importance of the adsorbates on the electron field emission of MWCNTs. For a contaminated MWCNT, although the field emission current was reduced, the stability of its emission was improved. A current of up to several tens of μA was observed for a single MWCNT, but it was found that long time emission usually results in drastic structure damage that may lead to sudden emission failure.     

Preparation,characterization, and adsorption properties for metal ions of a novel chelating resin containing sulfoxide and diethylene glycol

A novel chelating resin containing sulfoxide and diethylene glycol, poly{4‐vinylbenzyl‐[2‐2‐(hydroxyethyl)ethoxyl]sulfoxide} (PVESO) was synthesized using chloromethylated polystyrene (PS‐Cl) as material. Its structure was characterized by elemental analysis, infrared spectra, and scanning electron microscopy (SEM). The adsorption capacities of the resin for Hg²⁺, Ag⁺, Cu²⁺, Zn²⁺, and Pb²⁺ at various pH values were determined. The maximum adsorption capacities for Hg²⁺ and Ag⁺ were 1.56 and 0.75 mmol g^?1 respectively. The resin had high selectivity for Hg²⁺ and Ag⁺ over the pH range 1.0–7.0. The adsorption capacities for Hg²⁺ and Ag⁺ under competitive condition were also determined by batch experiment method. In addition, the adsorption kinetics of the resin towards Hg²⁺ at different temperatures was also investigated. The results showed that the adsorption rate was governed by film diffusion at 20°C and 25°C, by particle diffusion at 30°C and 35°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 6054–6059, 2006     

Propylene epoxidation in a microreactor with electric heating

Gas phase propylene epoxidation on gold catalysts has attracted wide attention from industry and academia due to its high selectivity. However, it suffers from low propylene conversion and rapid catalyst deactivation. Experiments showed that propylene conversion could be increased by raising H₂, O₂, or C₃H₆ concentration in the feed, but the feed compositions were within the explosion limit. It was also shown that the activity of the used catalyst could be fully recovered, but the regeneration temperature was 280 °C, much higher than that for reaction. Therefore a microchannel reactor was devised to suppress explosion and was constructed with Fecralloy, to raise the temperature rapidly for catalyst regeneration by electric heating. In two minutes the temperature of the reactor could be raised from 50 to 300 °C. Catalysts were coated on the alloy belt by dip coating, and the performance of the reactor was evaluated under different operating conditions. Results showed that in the microreactor the overall reaction rate was controlled mainly by the intrinsic reaction rate, and also influenced by film diffusion to a certain extent. The deactivated catalyst was regenerated in the microchannel reactor and the activity was fully recovered.     

近十年常温干法精脱硫专利技术发展动态

收集了近十年来国内的常温干法精脱硫专利，并分类列举出各种脱硫剂的物化性质和几种常温精脱硫工艺，重点阐述了该技术的优缺点及其未来发展方向。     

温度对工业汽轮机运行的影响

由于温度的变化，而引起机组热应力的变化，这是工业汽轮机运行中最主要的变化，它对机组的安全和运行影响非常大。     

Soap‐free emulsion copolymerization of perfluoroalkyl acrylates in the presence of a reactive surfactant

Soap‐free emulsion copolymerization of perfluoroalkyl acrylate (FA)/methyl methacrylate (MMA)/n‐butyl acrylate (n‐BA) was carried out in the presence of sodium 2‐acrylamide‐2‐methyl propanesulfonate (AMPSNa) as a reactive surfactant and potassium persulfate (KPS) as an initiator. An analysis of the effects of concentration of AMPSNa, KPS, FA as well as polymerization temperature on the kinetic features (rate of polymerization) and colloidal characteristics (mean particle diameter, particle disperse index, particle numbers, and surface charge density) was followed. NMR, FTIR, AFM, and fluorine‐selective electrode analysis were used to characterize the composition and morphology of the FA copolymers. Both AFM analysis and contact angle measurements strongly implied that the fluorinated segments migrated to the outmost surface and created films with lower surface energy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2438–2444, 2007     

Modification of silk with aminated polyepichlorohydrin to improve dyeability with reactive dyes

Reactive dyes have almost complete exhaustion and ideal fixation on aminated polyepichlorohydrin pretreated silk without addition of salt or alkali. The effects of varying pretreatments and dyeing conditions were studied. The dyeing behaviour of CI Reactive Red 15 on modified silk under pH 6 was investigated. Dyeings of modified silk showed good wash fastness, dry and wet rub fastnesses as well as light fastness. The quality of the dyed silks obtained after pretreatment was shown to be satisfactory and the dyeing effluent was less polluted.