【作者】 刘威；

【导师】 纪树兰；

【作者基本信息】 北京工业大学 ， 应用化学， 2014， 博士

【摘要】 生物发酵与渗透汽化耦合技术已被证明是一种高效节能的连续化生产生物质燃料的方法，这项技术的关键是发展高性能、稳定性好的渗透汽化膜材料。本论文以生物能源中的燃料乙醇、丁醇为背景，利用聚苯醚（PPO）的“刚性”分子链对聚二甲基硅氧烷（PDMS）的“柔性”分子链进行改性，合成一系列不同“软-硬”段比例的聚二甲基硅氧烷-聚苯醚嵌段（PDMS-b-PPO）共聚物；采用溶剂挥发法制备均质膜，研究醇和水分子在膜中的溶解扩散性能差异；采用相转化法制备出高通量的非对称膜，借助现代分析手段，考察膜的微观结构、形貌对醇/水分离性能的变化规律；进一步研究了溴取代的聚苯醚（BPPO），在陶瓷支撑体上交替组装BPPO和PDMS，原位制备了聚二甲基硅氧烷/聚苯醚交联共聚（c-PDMS/BPPO）膜。本研究将为优先透醇膜材料的结构设计和调控提供理论指导。首先，利用阳离子开环反应和基团取代反应制备了二甲胺基封端的聚二甲基硅氧烷，探讨了合成反应中的主要影响因素，并利用FTIR和元素分析仪对产物结构进行表征。通过自制的二甲胺基封端聚二甲基硅氧烷和商业化氨丙基封端聚二甲基硅氧烷分别与羟基封端的聚苯醚反应，利用聚合物分子链末端上的活性基团进行反应合成了聚二甲基硅氧烷-聚苯醚嵌段（PDMS-b-PPO）共聚物，从理论上分析了嵌段反应的可行性并摸索了适宜的反应条件，利用FTIR、NMR和DSC对PDMS-b-PPO共聚物的结构进行表征，对比了两种端基的PDMS和PPO反应的难易程度。其次，在不同原料比下合成了一系列PDMS含量不同的PDMS-b-PPO共聚物，通过溶剂挥发法将其制备成均质膜，考察了组分比对PDMS-b-PPO均质膜渗透汽化性能的影响。根据溶解度参数原则和Flory-Huggins相互作用参数理论，分别计算了PDMS-b-PPO膜的溶解度参数、渗透组分与PDMS-b-PPO膜的相互作用参数及其扩散系数，结合AFM、EDX、SAXS和DSC对PDMS-b-PPO膜的微观形貌和结构进行表征，探讨了PDMS-b-PPO膜的组分比对其热力学行为、动力学行为和宏观分离性能的影响。再次，通过相转化法制备了不同PDMS含量的PDMS-b-PPO非对称膜，采用SEM、EDX、XRD和AFM等手段对膜结构进行表征，研究了组分比对PDMS-b-PPO非对称膜微观形貌、表面疏水性及结晶性能的影响，考察了操作条件对PDMS-b-PPO非对称膜渗透汽化性能的影响。通过对比PDMS-b-PPO均质膜和非对称膜的微观形貌、热力学和动力学行为，从理论上解释了两种膜在宏观性能上的差别。结果表明，PDMS-b-PPO非对称膜显示了更高的渗透通量。当操作温度为60℃，铸膜液中聚合物浓度为11wt%，原料液乙醇浓度为5wt%时，渗透通量可达1400g·m^-2·h^-1。最后，利用Wohl-Ziegler反应制备了一系列溴化聚苯醚（BPPO），并通过控制光照时间调控BPPO的溴化率。在微滤陶瓷管式基膜上交替组装BPPO和PDMS，原位制备了PDMS/BPPO交联共聚（c-PDMS/BPPO）膜，并将其用于正丁醇/水的渗透汽化分离。结果表明，随着浸渍时间的增加，分离因子减小，通量增大；随着BPPO溴化率的增大，分离因子呈现出先增大后减小的趋势。当浸渍时间为1.33h，溴化率为34wt%时，c-PDMS/BPPO膜的性能较好，分离因子为35，通量为220g·m^-2·h^-1。另外，在200h的连续透正丁醇/水实验中，c-PDMS/BPPO膜呈现出较好的稳定性。这表明BPPO增强了PDMS的成膜性及耐溶胀性能。更多还原

【Abstract】 The coupling of fermentation and pervaporation for bio-fuel has been proven asan efficient and low energy consumption technology route. Researchers are alwaysfocus on the design of membrane which has high separation performance and stability,and the development of novel membrane materials with perfect separationperformance and good mechanical properties is the key point in pervaporation. Basedon the ground of ethanol and butanol in bio-fuel, this study synthesized thepolydimethylsiloxane-block polyphenylene oxide （PDMS-b-PPO） copolymers withdifferent composition, through the modification of PDMS by PPO. PDMS-b-PPOhomogeneous membranes were prepared by solvent evaporating method, and then thedifferent solubility and diffusion of ethanol and water in the membrane were studied.High flux PDMS-b-PPO asymmetric membranes were prepared by phase-inversionmethod, and the morphologies and pervaporation performance were studied.Furthermore, bromide-substituted polyphenylene oxide （BPPO） was synthesized,althernately assembled PDMS and BPPO on ceramic membrane for preparing thecross-linked-PDMS/BPPO membranes. This study is benefit to the design ofmembrane material for alcohol concentration.First, amido-terminated polydimethylsiloxane were synthesized by the methodsof positive ion ring-opening reaction and substitution reaction, the effect oftemperature, ratio of raw materials and the amount of end-capping reagent onsynthesis of amido-terminated polydimethylsiloxane were studied, and the productwas characterized by FTIR and element analysis.Orientation reaction between amidoor amine groups on PDMS chains and the hydroxyl groups on PPO chains wereconducted for obtaining the PDMS-b-PPO copolymers with different composition.The effects of temperature, ratio of raw materials and the amount of end-cappingreagent on synthesis of amido-terminated polydimethylsiloxane were studied, thePDMS-b-PPO copolymers were characterized by FTIR,1H-NMR, DSC, and thereaction between PPO with two different PDMS was compared.Second, a series of PDMS-b-PPO membranes with different PDMS content wereprepared by solvent evaporation method with suitable conditions. The permselectivityof these membranes were discussed as the variety of PDMS content. According to theFlory-Huggins principle, the solubility parameters of PDMS-b-PPO membranes, theinteraction parameters of ethanol and water with membrane, the diffusion parameterswere calculated, and the morphologies of PDMS-b-PPO membrane werecharacterized by AFM, EDX, SAXS and DSC, the relationship of PDMS content withthe thermodynamic of PDMS-b-PPO membranes was studied. Third, a series of PDMS-b-PPO asymmetric membranes with different PDMScontent have been prepared by phase-inversion process, the morphologies of thesemembranes were characterized by SEM, EDX, XRD and AFM, and the effect ofPDMS content on the morphology, hydrophobility and crystallization of themembrane, and the effect of operation conditions on the pervaporation performance ofPDMS-b-PPO asymmetric membranes with different PDMS content were studied.The differences of separation performance of PDMS-b-PPO homogeneous andasymmetric membranes were discussed by comparing the morphologies andthermodynamics of these two membranes. The results showed that the PDMS-b-PPOasymmetric membrane shows better flux than that of PDMS-b-PPO homogeneousmembrane. When polymer concentration in casting solution was11wt%, operatingtemperature was60℃, feed concentration was5wt%and the flux was1400g·m^-2·h^-1.At last, a series of BPPO with different bromide-substituted ratio were firstlysynthesized through Wohl-Ziegler reaction, and the bromide-substituted ratio ofBPPO was controlled by illumination time. An in-situcross-linked-polydimethylsiloxane/brominated polyphenylene oxide（c-PDMS/BPPO） membrane on ceramic tube has been prepared for the recovery ofbutanol by pervaporation. BPPO and PDMS were sequentially assembled and in-situcross-linked to form the final c-PDMS/BPPO membrane. As the results shown, theseparation factor increased and the flux decreased as the increase of dipping time. Onthe other hand, the separation factor increased first and then decreased as the increaseof bromide-substituted ratio of BPPO. The pervaporation experiments ofbutanol-water mixture indicated that the c-PDMS/BPPO membrane exhibited anacceptable flux of220g·m^-2·h^-1and high separation factor of35towards butanol,when the bromide-substituted ratio was34wt%and the dipping time was1.33h.Moreover, the c-PDMS/BPPO membrane performed excellent stability in an about200h continuous butanol recovery, as compared to the PDMS membrane.更多还原