N-异丙基丙烯酰胺凝胶在NaCl水溶液中溶胀行为的预测研究

In this paper, a model is presented to correlate and predict the swelling behavior of hydrogels in aqueous solutions of electrolytes. The model is a combination of VERS-model, “phantom network“ theory and “free-volume“ contribution. The VERS-model is used to calculate Gibbs excess energy; “phantom network“ theory to describe the elastic properties of polymer network, and “free-volume“ contribution to account for additional difference in the size of the species. To test the model, a series of N-isopropylacrylamide based hydrogels are synthesized by free radical polymerization in oxygen-free, deionized water at 25~C under nitrogen atmosphere. Then, the degree of swelling of all investigated gels as well as the partition of the solute between the gel phase and the surrounding coexisting liquid phase are measured in aqueous solution of sodium chloride. The model test demonstrates that the swelling behavior correlated and predicted by the model agrees with the experimental data within the experimental uncertainty. The phase transition appeared in the experiment, and the influences of the total mass fraction of polymerizable materials ξgel as well as the mole fraction of the crosslinking agent YCR on the swelling behavior of IPAAm-gels can also be predicted correctly. All these show the potential of such model for correlation and prediction of the swelling behavior of hydrogels in aqueous solutions of electrolytes.     

染料刚果红的光催化降解过程研究

在考察光催化降解优化条件的基础上,侧重研究了刚果红的光催化脱色与矿化之间的关系,结果表明刚果红的光催化降解首先是生色基团破坏而脱色,并伴随酸化最后才被矿化,即矿化发生在脱色之后,两者并非同时进行.     

芳烃污染空气光催化净化材料研究进展与展望

芳烃化合物是一类难降解的有毒挥发性有机物,排放到大气对生态环境有极大的危害。光催化技术作为一种高级氧化技术是未来环境净化技术的发展方向之一。然而,经典的TiO2材料对芳烃的光催化氧化,不仅活性低而且极易失活,这在很大程度上制约了光催化技术在空气净化领域的实际应用。在综述国内外研究进展的基础上,简要总结了最近几年我们在芳烃污染空气的光催化净化材料开发和性能研究方面的一些进展。研究结果显示,有众多宽带隙半导体材料对芳烃表现出比TiO2更加优异的光催化活性和活性稳定性;有些材料甚至在可见光诱导下可表现出非常高的光催化活性。此外,在反应气氛中添加少量氢气可以大幅度提高贵金属修饰TiO2对苯的光催化降解效率。这些进展充分显示出光催化技术在工业三苯废气处理和空气净化等方面的广阔应用前景。     

化学武器及其模拟剂的光催化消除研究进展

光催化不仅在环境污染治理等方面有着潜在而广泛的应用背景,并且在军事防化领域还有重要的实际应用价值.笔者评述了目前光催化在军事防化领域的研究概况,并对存在的问题和未来的发展动向进行简要分析.     

纳米Fe3O4磁性粒子的制备及物性研究

利用滴定水解法制备了Fe₃O₄纳米颗粒,经XRD和漫反射吸收谱分析,Fe₃O₄晶粒粒径约为18nm,从紫外至近红外(200～3000nm)均有很强的光吸收。纳米Fe₃O₄有明显的负磁阻和湿敏效应,其阻抗随磁感应强度和湿度的增大而减小。     

Prediction of Swelling Behavior of AT-Isopropylacrylamide Hydrogels in Aqueous Solution of Sodium Chloride

In this paper, a model is presented to correlate and predict the swelling behavior of hydrogels in aqueous solutions of electrolytes. The model is a combination of VERS-model, "phantom network" theory and "free-volume" contribution. The VERS-model is used to calculate Gibbs excess energy; "phantom network" theory to describe the elastic properties of polymer network, and "free-volume" contribution to account for additional difference in the size of the species. To test the model, a series of N-isopropylacrylamide based hydrogels are synthesized by free radical polymerization in oxygen-free, deionized water at 25℃ under nitrogen atmosphere. Then, the degree of swelling of all investigated gels as well as the partition of the solute between the gel phase and the surrounding coexisting liquid phase are measured in aqueous solution of sodium chloride. The model test demonstrates that the swelling behavior correlated and predicted by the model agrees with the experimental data within the experimental uncert     

四丁基锡在Pt/HY分子筛表面的接枝反应及其催化性能的研究

研究了真空条件下四丁基锡(SnBu4)在Pt/HY分子筛超笼表面的接枝反应,并用元素分析、ICP、GC-MS、XRD、FTIR、TG、BET、UV-Vis等方法对产物的组成、结构和性质进行了表征。研究结果表明,SnBu4与Pt/HY分子筛表面羟基可以定量、有选择性地进行化学反应,将确定数目的SnBu3碎片接枝在分子筛的超笼中。经SnBu4改性后的Pt/HY分子筛的骨架结构没有被破坏,接枝反应发生在分子筛表面,BET比表面积和孔体积变小,表面性质发生变化。将改性后的Pt/HY分子筛应用于糠醛气相氢化反应,糠醇的选择性明显增加。     

光催化材料在太阳能转换与环境净化方面的研究现状和发展趋势

本文简要评述了光催化材料在太阳能转化和环境净化方面应用的研究背景、现状和发展趋势。     

二甲氨基异丙氧基铜(Ⅱ)在MCM-41表面的化学接枝

首次研究了高真空条件下二甲氨基异丙氧基铜(∏)与MCM-41分子筛的接枝反应,并用元素分析、ICP、XRD、FTIR、TGA、N2吸附和UV-Vis等方法对产物的组成、结构和性质进行表征,初步研究结果表明,两者在室温下可以发生化学反应,导致其完整地接枝在分子筛表面.     

无机防污闪薄膜的制备和性能

将TiO2光催化剂固化在高压绝缘子表面形成无机防污闪薄膜,用XRD、UV-Vis、FT-IR和SEM表征和测试了薄膜的结构和光催化活性,比较了高压绝缘子涂覆光催化薄膜前后电气性能的变化和实挂的积污情况.结果表明,镀膜后的绝缘子电气性能变化不大,挂网6个月后样品表面的灰密值为镀膜前的1/35.在满足电气性能的前提下,镀膜后的绝缘子具有良好的光自洁能力和防污闪性能.