微乳液模板法制备色氨酸分子印迹膜及其性能研究

发布时间：2018-07-10 12:26

  本文选题：分子印迹膜 + 微乳液聚合　； 参考：《福州大学》2011年硕士论文

【摘要】：本文将微乳液聚合和分子印迹技术相结合，提出微乳液模板法制备分子印迹膜（MIM）的新方法。采用L-色氨酸（L-trp）为模板分子，以双连续相微乳液为孔穴模板，并在较低温下引发聚合制备MIM。考察了影响MIM选择吸附性能和膜孔结构的因素，研究MIM的膜孔形态及分离过程识别机理。 对微乳液拟三元相图和电导率研究，发现L-trp和丙烯酰胺（AM）对体系具有助乳化效果，且L-trp有助于双连续相微乳液的形成。油相单体中MMA/BA的比对反相微乳液区影响较大。确定微乳液印迹体系为MMA-BA/AA/H2O/L-trp，体系通过KPS/TMEDA氧化还原引发剂引发聚合成膜，考察了影响MIM的选择吸附性能和膜孔结构的因素。结果表明，交联剂EGDMA的加入，能维持MIM的印迹孔穴形态和膜孔结构的稳定性。随着微乳液印迹体系中水相分率的提高，MIM的吸附量Q和水通量F增加，但水相分率过高容易引起聚合过程发生的微观相分离，导致MIM中的印迹层和膜孔结构的破坏。AA与MIM结合位点和膜孔大小密切相关，AA含量过多会降低选择吸附性能和水通量，AA/MMA-BA比控制在2.5，既能维持微乳液聚合的稳定性，同时又能确保MIM较好的性能。MMA能够维持印迹孔穴的刚性结构，但MMA含量过多则会影响孔穴的空间构型。随着L-trp增加，MIM的水通量F提高，但过量L-trp使印迹位点的利用率下降，选择吸附性能相应下降。所以，当EGDMA的含量在2.0%，水相分率为40%，AA/MMA-BA为2.5，MMA/BA为2.0，L-trp含量为0.9%时，，分离因子α和水通量F较大，表现为较佳的选择识别性能和膜孔结构。 通过SEM观察，MIM的孔道维持了双连续相的海绵状孔道结构。MIM的膜孔径和对L-trp的渗透量随着水相分率的提高都增大。MIM对L-trp吸附在120min内可达到吸附平衡，结合MIM渗透过程和红外谱图分析，发现L-trp与MIM中的结合位点存在氢键作用，且MIM对L-trp的渗透是一个优先吸附并逐步透过的过程。MIM耐酸性能较好，但耐碱性较差，在碱溶液中发生不可逆溶胀。热重结果表明MIM具有较好的热稳定性。MIM在20~50℃的热处理会引起膜的致密，渗透性能降低；但温度达60℃则会引起膜孔结构的破坏。
[Abstract]:In this paper, a new method of preparing MIM by microemulsion template was proposed by combining microemulsion polymerization with molecular imprinting. Using L-Tryptophan (L-trp) as template molecule and double continuous microemulsion as pore template, Mims were prepared by polymerization at low temperature. The factors affecting the selective adsorption properties and membrane pore structure of MIM were investigated, and the membrane pore morphology and separation process identification mechanism of MIM were studied. The pseudo-ternary phase diagram and electrical conductivity of microemulsion were studied. It was found that L-trp and acrylamide (AM) could help emulsify the microemulsion, and L-trp was helpful to the formation of double-continuous microemulsion. The ratio of MMA / BA in oil phase monomer has a great influence on the area of inverse microemulsion. The microemulsion imprinting system was determined as MMA-BA / A / H _ 2O / H _ 2O _ L-trp.The system was polymerized by KPS / TMEDA redox initiator. The factors affecting the selective adsorption properties and pore structure of MIM were investigated. The results showed that the addition of crosslinking agent EGDMA could maintain the stability of MIM imprinted pore morphology and membrane structure. With the increase of water phase separation rate in microemulsion imprinted system, the adsorption capacity Q and water flux F of MIM increase, but the high water phase separation rate easily leads to the microphase separation in the polymerization process. As a result of the destruction of the imprinted layer and membrane pore structure in MIM. AA is closely related to MIM binding sites and membrane pore size. Excessive AA content will reduce the selective adsorption performance and the water flux ratio of AA / MMA-BA to 2.5, which can maintain the stability of microemulsion polymerization. At the same time, it can ensure the better performance of MIM. MMA can maintain the rigid structure of imprinted pores, but too much MMA content will affect the spatial configuration of the pores. With the increase of L-trp, the water flux F of MIM increased, but excessive L-trp decreased the utilization of imprinted sites and the selective adsorption ability. Therefore, when the content of EGDMA is 2.0 and the water phase separation rate is 40. 5% MMA-BA is 2.5% MMA / BA is 2.0% L-trp content is 0.9, the separation factor 伪 and water flux F are larger, showing better selective recognition performance and membrane pore structure. It was observed by SEM that the membrane pore size and the permeability to L-trp increased with the increase of water phase separation. The adsorption equilibrium of L-trp adsorbed in 120min was achieved. Combined with MIM osmotic process and IR spectrum analysis, it was found that the binding sites of L-trp and MIM had hydrogen bond interaction, and the permeation of L-trp by MIM was a preferential adsorption and gradual permeation process. MIM had good acid resistance, but poor alkali resistance. Irreversible swelling occurs in alkali solution. The thermogravimetric results show that MIM has good thermal stability. The heat treatment of MIM at 20 ~ 50 鈩

本文编号：2113393