HT-730改性酚醛-丁腈胶粘剂的研制

对酚醛-丁腈胶粘剂进行改性，添加5．0％的硅烷偶联剂，改善了酚醛-丁腈胶粘剂的工艺性能，提高了粘接强度，特别是降低了酚醛-丁腈胶对环境湿度的敏感性。研制的HT-730胶在环境湿度90％时仍有很高的粘接强度，同时老化性能和适用期并没有受到影响。     

射流流化床内流体力学行为的模拟研究

以流化床应用为代表的气固流动系统是许多化工过程中的重要组成部分 ,CFD( computational fluid dynamics)方法能够为其优化设计和放大提供所需要的信息 .本文采用双欧拉模型 ,与 Gidaspow等的实验结果进行了对比 ,模拟了二维射流流化床内气泡的形成规律 ,得到了带锥型分布器的流化床内瞬时空隙率和气固相速度分布等流体力学参数 .对锥型分布器流化床的实验结果表明 ,模拟得到的气泡的形状与实验现象相接近 .     

New polyimide–silica organic–inorganic hybrids

A series of polyimide–silica hybrid films with silica contents up to 30 wt % were successfully prepared by the sol‐gel reaction of tetraethoxysiliane in the presence of poly(amic acid) containing pendent hydroxyl groups. The films were yellow and transparent when the silica content was less than 11 wt %. The chemical structure of the films was characterized by Fourier transform infrared spectroscopy, and the morphology of the films was investigated by scanning electronic microscopy and atomic force microscopy. Thermogravimetric analysis, differential scanning calorimetry, and stress–strain tests were used to measure the performance of the films. The results indicate that the glass‐transition temperatures and decomposition temperatures of the hybrid films increased with increasing silica content, whereas the tensile strength had a maximum with the variety of silica contents. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2210–2214, 2003     

Seeded Crystallization of Leucite

The leucite crystallization kinetics from a hydrothermally derived precursor seeded with nano-crystalline leucite was investigated by X-ray diffraction and non-isothermal differential thermal analysis. The nano-crystalline leucite was prepared by high-energy milling of high-purity leucite powder and the leucite precursor was prepared by the hydrothermal method of silica sol, aluminum nitrate, and potassium nitrate. After the seeds were introduced, the crystallization temperature of the precursor was lowered by 100°C and the transition phase kalsilite did not appear during the crystallization process. When the seeded precursor was heat treated at 700°C, a small amount of cubic leucite was stabilized to room temperature. The seeded precursor showed an exothermic peak between 800° and 920°C under different heating rates. The activation energy for the growth of leucite from the seeded precursor was 256(SD9) kJ/mol.     

Decolorisation and mineralisation of CI Reactive Black 8 by the Fenton and ultrasound/Fenton methods

The effects of pH, ferrous ion and hydrogen peroxide dosage on the decolorisation and mineralisation of CI Reactive Black 8 by the Fenton process with/without ultrasonic irradiation were investigated. It was verified that the presence of ultrasonic irradiation did not enhance the decolorisation of CI Reactive Black 8 significantly by Fenton's reagents, but it enhanced the chemical oxygen demand removal efficiency. The enhancement was more pronounced for lower (<0.89 mm) or higher (>1.78 mm) ferrous ion dosage. The optimal pH for chemical oxygen demand removal was 3.0. Chemical oxygen demand removal efficiency increased with the increasing H₂O₂ dosage and reached the highest level at 5.88 mm, but further increase in H₂O₂ dosage would not increase removal efficiency significantly.     

Preparation,characterization, and some physical properties of polypropylene/poly(methyl acrylate)‐grafted glass wool composites

Polypropylene/poly(methyl acrylate)‐grafted glass wool (PMA‐g‐GW) mixes were prepared. The polymerization process was carried out using potassium persulfate (PPS) and PPS/acetone sodium bisulfite (ASBS) as a redox‐pair initiation system at 60 and 70°C. The effect of using PPS or PPS/ASBS on the grafting percent and conversion percent reveals that the conversion percent values on using PPS as an initiator are higher than those of PPS/ASBS, while in the case of grafting, the inverse is true, that is, using PPS as an initiator gives grafting percent values lower than those that can be obtained using PPS/ASBS. The dielectric properties, thermal diffusivity, specific heat capacity, and thermal conductivity of PP loaded with modified glass wool as a function of different types and concentrations of initiators—used in the grafting polymerization process, namely, PPS and the redox initiating system—were also studied. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 723–732, 2003     

Monodisperse polymer/metal composite particles by electroless chemical deposition: Effect of surface functionality of polymer particles

Micron‐sized polymer particles were coated with layers of nickel compounds by plating electrolessly in the presence of aqueous solutions of nickel chloride, sodium hypophosphite, sodium citrate, and ammonium chloride at elevated temperature. The uniform functional polymer particle could be obtained by seeded polymerization. To investigate the effect of surface functionality on the conditions for nickel deposition, the polymer particle was functionalized with the thiol group. From morphological observation, it was found that the mode of nickel deposition was greatly dependent on the surface functionality of the polymer particle. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 420–424, 2003     

Vinyl‐containing silicone resin as the crosslinking agent of heat‐curable silicone rubber

Heat‐curable silicone rubber (HCSR) was prepared by using vinyl‐containing silicone resin (VSR) as the crosslinking agent instead of polyvinylsilicone oil (C gum). Mechanical properties and crosslink density of the vulcanizates were measured. The results indicate that VSR is a good crosslinking agent for HCSR. The tensile strength, tearing strength, elongation at break, and hardness of the vulcanizate can reach 10.2 MPa, 29.1 kN/m, 720%, and 58 SHA, respectively. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 3123–3127, 2002; DOI 10.1002/app.10054     

以显微荧光检验法检测常用盖印材料

显微荧光检验法是显微检验的一个重要角度,由于缺少基础性研究,这一方法在文件检验中的运用并不广泛.着重考虑曝光时间这一因素,以盖印材料的荧光特性为观察角度,运用显微荧光检验法对大量常用盖印材料进行系统、全面的观察和研究.研究表明,绝大部分盖印材料可被激发出荧光,每种盖印材料的荧光特性都有各自的规律性特点.     

Morphologies-Controlled Synthesis and Optical Properties of Bismuth Tungstate Nanocrystals by a Low-Temperature Molten Salt Method

Well-crystallized bismuth tungstate (Bi₂WO₆) powders with different morphologies were successfully synthesized via a low-temperature molten salt method. The powders were characterized by X-ray diffraction, transmission electron microscopy, and UV-Vis, respectively. It was found that the variation of morphology of the obtained Bi₂WO₆ powder mainly depends on the different reaction temperatures and the weight ratio of LiNO₃–NaNO₃ salt to precursor. In addition, the UV-Visible absorption spectra showed that the synthesized powders had strong light absorption properties not only in the ultraviolet light but also in the visible light region.