磁性壳聚糖微球的合成及其在固定化血管紧张素转化酶的应用

以化学共沉淀法合成Fe3O4纳米粒子为磁核,采用乳化交联法制备磁性壳聚糖微球,并对其形貌、结构和磁饱和强度等性质进行了表征。以磁性壳聚糖微球作为载体,固定化猪肺粗提物中的血管紧张素转化酶,并对固定化条件进行研究。结果表明,固定化血管紧张素转化酶的最佳条件为：pH值为8.3,最佳温度为50 ℃,最佳时间为1.5 h,最佳酶溶液蛋白浓度为6 mg/mL,此时固定化酶活力最高为0.048 U/g微球。与游离酶相比,固定化酶的pH值稳定性和热稳定性均得到提高。固定化酶重复使用10次,仍然保持40%以上相对活力,说明磁性壳聚糖微球是固定化血管紧张素转化酶的良好载体。     

Grafting of titanium dioxide microspheres with a temperature‐responsive polymer via surface‐initiated atom transfer radical polymerization without the use of silane coupling agents

Titania microspheres with narrow size distribution and diameters of about 1 µm were prepared and subsequently functionalized using surface‐initiated atom transfer radical polymerization (ATRP) of N‐isopropylacrylamide. The ATRP initiator was immobilized on the particle surface via acylation of surface hydroxyl groups with α‐bromoisobutyryl bromide. Subsequently, an established ATRP reaction system was used for the preparation of titania surface‐grafted poly(N‐isopropylacrylamide) (PNiPAAm). Characterization was performed with electron microscopies, X‐ray diffraction, infrared spectroscopy and dynamic light scattering. It was found that the particle size in aqueous dispersions changed reversibly with temperature as expected for a shell of PNiPAAm, a polymer with a lower critical solution temperature at 32 °C. This confirmed the successful preparation of functional, stimuli‐responsive TiO₂ microparticles via a straightforward controlled surface‐initiated polymerization method.     

New Semi-Interpenetrating Polymeric Networks from Linear Polysulfone and Thermosetting Bismaleimide and Polyaminobismaleimide Resins

New semi-interpenetrating (semi-IPN) polymeric networks from commercial polysulfone (UDEL RP-1700) and thermosetting bismaleimide (4, 4'-bismaleimidodiphenylmethane) (BMDM) and maleimide terminated polyaminobismaleimide prepolymer based upon BMDM and 4, 4'-diaminodiphenylmethane were prepared. The chemistry, processing, physical and mechanical properties, phase morphology, thermal stability and solvent resistance of the neat resins are presented. The interrelationships among structure, processing, propcrties, and morphology are also discussed.     

STUDY ON THE SEPAEATION OF A BINARY METAL MIXTURE BY SOLVENT EXTRACTION

A study on the extraction of copper and zinc from aqueous binary metal solutions with terdodecylthioglycolic acid in kerosene has been realized. Distribution of the metal ions in a wide range of pH and carboxylic acid concentrations has been studied.The results show that an interaction occurs which influences the amount of each metal extracted, so that a mixed metal complex is formed in the organic phase, in addition to pure metal complexes and . The separation factor for copper and zinc has been expressed as a function of the species concentrations and the extraction constants involved. From these results, the extractant is shown to be moderately adequate for separation of copper and zinc.     

A QUASI NEWTONIAN MODEL FOR SIMULATING THE FLOW OF DILUTE POLYMER SOLUTIONS THROUGH A SUDDEN CONTRACTION

The flow of a quasi Newtonian model fluid, which allows shear thinning as well as extension thickening, through a sudden planar 4:1 contraction is studied numerically. Comparing with numerical results for a purely shear thinning fluid differences show up which follow the trend of experimental data.     

A novel copolymer of N-[(tert-butylperoxy)methyl]acrylamide and maleic anhydride for use as a reactive surfactant in emulsion polymerization

A new copolymer of N-[(tert-butylperoxy)methyl]acrylamide (tBPMAAm), containing a primary–tertiary peroxide group and maleic anhydride (MA), was synthesized and employed as a reactive surfactant (inisurf) for the emulsion polymerization of styrene to yield surface-functionalized (peroxidized) reactive latex particles. The copolymerization characteristics were analyzed to determine the monomer reactivity ratios and to provide a way to control the copolymer composition. The ability of tBPMAAm–MA to act as a reactive surfactant during emulsion polymerization was confirmed by the synthesis of monodisperse polystyrene latexes of varying particle size. In addition, peroxide groups were localized on the surface of the particles in a controllable amount (depending on the copolymer concentration), thus, providing the opportunity for further modification of the surface of the particles. This novel copolymer is expected to be a promising and efficient material in the synthesis of functional polymer nanoparticles with well-defined core–shell morphologies.     

电磁场对聚合硫酸铁水解聚合物形态分布及其混凝性能的影响

为了提高聚合硫酸铁的混凝性能,增强对污水的去除能力.利用自制交流变频磁化装置,对聚合硫酸铁溶液进行磁化处理,以铁盐水解形态Feb为指标,交流变频电磁场的频率、电压、电流及磁化时间为实验因素,对电磁场作用下的聚合硫酸铁溶液进行形态分析,并与非磁化的PFS溶液进行对比;以高炉煤气洗涤水为实验水样,通过混凝试验对比聚合硫酸铁溶液磁化前后的出水浊度及COD值.研究结果表明:电磁场作用下的聚合硫酸铁溶液的形态分布发生了变化,与非磁化相比,Feb百分比含量增加了1倍,Fec百分比含量减少了1/3,且当频率为300 Hz、电压为100 V、电流为0.8A、磁化时间为2 min时Feb的百分比含量达到最大;电磁场能明显提高聚合硫酸铁的混凝性能,与非磁化的聚合硫酸铁溶液相比出水浊度与COD值降为原来的一半,投药量节省了1倍.     

多孔淀粉基炭微球的制备及其在双电层电容器中的应用

通过简单的无机盐磷酸氢二铵催化稳定化、炭化及不同碱炭比KOH活化制备了高比表面积的多孔淀粉基炭微球材料。采用电子扫描显微镜（SEM）、高分辨透射电子显微镜（HRTEM）及N₂吸脱附测试对实验所制得的炭微球样品的形貌及孔结构进行了分析。结果表明：不同KOH碱炭比制备的多孔淀粉基炭微球材料具有较大的比表面积（﹥2 300 m²/g）,且均含有大量的大孔和微孔,在6 mol/L的 KOH电解液对称的双电层电容器中多孔淀粉炭材料表现出优异的电化学性能,在100 A/g的大电流密度下,炭微球电极材料具有最大的质量比电容高达248 F/g。     

纳米橡胶改性环氧水下结构胶的研制及应用

介绍了应用纳米橡胶改性环氧作水下结构胶之研制过程,其中针对水下固化粘接机理、纳米橡胶在环氧胶粘剂中的增韧机理、特种水下固化剂的选用、自制润湿剂的合成、纳米无机粉料的触变作用等进行优化组合开发出具有高强度的结构胶,并应用于水下粘接、堵漏、补强加固等方面。