【作者】 项雯；

【导师】 吴礼光；

【作者基本信息】 浙江工商大学 ， 环境工程， 2011， 硕士

【摘要】 本文选用聚氧乙烯-聚氧丙烯-聚氧乙烯(PEO-PPO-PEO, F127)三嵌段共聚物作为表面活性剂,可聚合的甲基丙烯酸甲酯(MMA)为油相,通过反相微乳液及其聚合技术制备了包含纳米AgCl粒子的F127-PMMA(聚甲基丙烯酸甲酯)有机-无机杂化膜,用于苯/环己烷体系的渗透汽化分离,主要研究内容包括以下几个方面：1、F127/MMA/(H2O+NaCl)和F127/MMA/(H2O+AgNO3)微乳液体系最大增溶水量(ωmax)及其稳定性的研究通过电导率法考察了微乳液体系ωmax及其稳定性,结果发现：(1)以F127作为乳化剂形成的F127/MMA/(H2O+NaCl)和F127/MMA/(H2O+AgNO3)微乳液只能是反相微乳液,并且其可控范围较窄；(2)F127浓度对反相微乳液体系的ωmax影响不大；(3)水相中NaCl浓度对F127/MMA/(H2O+NaCl)反微乳液体系的ωmax影响不大,而水相中AgNO3浓度对F127/MMA/(H2O+AgNO3)反微乳液体系的ωmax有较大影响。2、反相微乳液体系中AgCl纳米粒子的结构调控及表征纳米AgCl粒子的形成和粒径的变化与反相微乳液体系的增溶水量ω、盐的浓度(Csalt)以及F127的浓度(CF127)有关。实验采用紫外-可见吸收(UV-vis)光谱、透射电镜(TEM)分析了纳米AgCl粒子在反相微乳液体系中的形成及粒径变化规律。(1)与小分子表面活性剂比较,以分子量较大的F127作表面活性剂时,纳米AgCl粒子的形成、生长和凝聚需要较长的时间,制得的纳米AgCl粒子的粒径均小于10 nm,粒径分布范围较窄。(2)随着微乳液体系中ω的增大,AgCl纳米粒子的平均粒径变大,粒子数目明显减少,但是当ω达到18以后,AgCl粒子的粒径略有下降,紫外可见光谱和TEM结果一致。(3)增加微乳液体系中的Csalt’有利于获得更多更小的纳米AgCl粒子。但是随着微乳液体系中的Csalt的进一步增加,在形成AgCl粒子的同时,也形成纳米Ag粒子。(4)随着微乳液体系中乳化剂的浓度增大,纳米AgCl粒子粒径和数目均增大。3、AgCl/PMMA-F127杂化膜的研制及其渗透汽化性能的研究利用微乳液聚合技术制备了AgCl/PMMA-F127均质膜和复合膜,采用扫描电镜(SEM)分析纳米AgCl粒子在杂化膜中的分布情况,分析结果显示：AgCl纳米粒子呈球状结构且均匀分散在杂化膜中,未出现明显的团聚现象,膜的致密性较好。复合膜对苯/环己烷体系的渗透汽化性能测试结果表明：当ω小于14时,随着微乳液体系中ω的增加,杂化膜的渗透通量和分离因子同时增大,当ω大于14时,杂化膜的分离因子开始减小；随着微乳液体系中Csalt和CF127的增加,杂化膜的分离因子表现出先增大后减小的趋势。论文研究表明,通过改变微乳液体系中ω、Csalt、CF127等因素可以调控生成的纳米AgCl粒子粒径和数量,从而改变AgCl/PMMA-F127杂化膜的结构形貌及渗透汽化分离性能。更多还原

【Abstract】 AgCl nanoparticles were first synthesized in water-in-oil microemulsion using poly (ethylene oxide)-poly (propylene oxide)-poly (ethylene oxide) block copolymers (F127) as a surfactant and polymerizable methyl methacrylate (MMA) as oil phase. Then AgCl/PMMA-F127 inorganic-organic hybrid membranes were prepared by situ-polymerization. Pervaporation performances of hybrid membrane were tested for separation of benzene/cyclohexane mixtures. The research content in this paper included three sections.1. Study of the stability and the maximum water solubilization capacity (ωmax) of F127/MMA/(H2O+NaCl) and F127/MMA/(H2O+AgNO3) microemulsionThe stability of microemulsion was analyzed via the measurement of conductivity. (1) F127/MMA/(H2O+NaCl) and F127/MMA/(H2O+AgNO3) microemulsion could only form reverse micriemulsion when F127 was used as surfactant. (2) The concentration of F127 had little effect on theωmax; (3) The concentration of NaCl influenced slightly on theωmax of F127/MMA/(H2O+NaCl) reverse microemulsion, whereas the concentration of AgNO3 had obviously impact on the F127/MMA/(H2O+AgNO3) reverse microemulsion.2. Characterization of the formation and morphology of AgCl nanoparticles in reverse microemulsion Several important factors affected the numbers and the size of AgCl nanoparticles in synetheis of AgCl nanoparticles via reverse microemulsion, such as molar ratio of water to surfactant (water solubilitation,ω), the concentration of salt and surfactant. The formation and morphology of AgCl nanoparticles were analyzed by ultraviolet-visible (UV-vis) spectrum and transmission electron microscopy (TEM). (1) The formation of AgCl nanoparticles in F127 microemulsion spent more time than those in microemulsion using AOT as surfactant. The sizes of all particles were less than 10 nm and its distribution was narrow. (2) The size of AgCl nanoparticles increased first withωincrease then decreased slightly after theωreached 18. The numbers of AgCl nanoparticles decreased withωincrease. (3) More AgCl nanoparticles with smaller size would be formed with increase of NaCl (AgNO3) concentration. However, there were Ag particles appeared simultaneously at high concentration of reactant salt, with the formation of AgCl nanoparticles. (4) The size and the numbers of AgCl nanoparticle increased as the F127 concentration increased.3. Study on AgCl/PMMA-F127 hybrid membranes for pervaporation of benzene/cyclohexane mixturesThe AgCl/PMMA-F127 homogeneous membranes and composite membranes were prepared by microemulsion polymerization. (1) The structure of hybrid membrane were analyzed by scanning electron microscope (SEM), and the resultes indicated that the AgCl nanoparticles in spherical shape were well dispersedand and did not aggregated obviously in the hybrid membrane. The hybrid membrane was dense membrane. (2) The performance of composite membranes was tested by pervaporation experiment of benzene/cyclohexane mixtures. The flux and selectivity of the membrane increased and then decreased with the increase ofω. The flux and selectivity of the membranes first increased and then decreased with the increase of concentration of salt and F127.In conclusion, there were many important factors influences on the size and numbers of AgCl nanoparticles, incldingω, the concentration of salt and surfactant. Then the AgCl-PMMA/F127 membranes were regulated by changing of these factors.更多还原