【作者】 胡耀东；

【导师】 曹丽琴； 王吉德；

【作者基本信息】 新疆大学 ， 化学， 2010， 硕士

【摘要】 二氧化碳由于其无毒、价格便宜、临界温度,压力适中(31.1°C,7.38 MPa),具有类似液体的黏度、气体的扩散性,因此,超临界二氧化碳(scCO2)在分离、高分子合成、材料处理等领域成为代替传统有机溶剂的一种绿色溶剂。本文以scCO2为聚合反应介质,展开了如下工作:(1)在scCO2中以乙二醇二甲基丙烯酸酯为交联剂制备了交联聚(N-异丙基丙烯酰胺)微粒,通过改变引发剂、交联剂的用量,以及调节CO2的温度、压力制备出干燥、均一、白色的交联PNIPA粉末,交联结构的PNIPA凝胶不仅在水中表现出溶胀性能,而且在无水乙醇中溶胀性能更良好。这些性质可能使其在生物医用领域有潜在价值。(2)在scCO2中制备了交联聚(4-乙烯基吡啶)。实验以4-乙烯基吡啶为单体,N, N/-亚甲基双丙烯酰胺为交联剂,通过沉淀聚合得到了微黄色、干燥粉末,在反应压力为14 MPa,温度为70oC时,适当交联剂用量下,产率可达80%。(3)在scCO2中,以4-乙烯基吡啶为功能单体,(S)-萘普生为模板,乙二醇二甲基丙烯酸酯为交联剂,制备出对(S)-萘普生有选择吸附性能的分子印迹聚合物。在乙腈中进行平衡吸附,印迹聚合物与非印迹聚合物相比表现出了较高的选择吸附性能;Scatchard分析表明,在研究浓度范围内,所制备的分子印迹聚合物具有两类亲和力结合位点,其高、低平衡离解常数分别为:Kd1 =0.50 mmol L-1,Kd2 = 5.3 mmol L-1,表观最大结合量分别为:Qmax1 = 25.5μmol g-1,Qmax2 = 82.2μmol g-1。更多还原

【Abstract】 Carbon dioxide is inexpensive, nontoxic, and non-flammable, and it has an easily accessible critical temperature of 31.1°C and critical pressure of 7.38 MPa, and it has both liquid and gas like characteristic. So the use of scCO2 as an alternative to traditional aqueous and organic solvents has attracted much attention in the fields of extraction, polymer synthesis and materials processing. The present study investigates the feasibility of using scCO2 as a polymerization medium for the following research work:(1) Cross-linked Poly (N-isopropylacrylamide) microparticles using ethylene glycol dimethacrylate as cross-linker were prepared in scCO2. It is possible to obtain uniformly dispersed particles by changing the initial concentrations of initiator, cross-linker and pressure as well as reaction time. The polymers were obtained in high yield as dry, fine and free flowing materials directly from the reaction vessel; The network showed not only easily swelled in deionized water but have relatively high swelling in pure ethanol. This shows the potential of the polymer in bio-medical applications.(2) Cross-linked Poly (4-vinylpyridine) (P4-VP) were synthesized in scCO2. The slight yellow, dry, fine powders were obtained directly from precipitation polymerization of 4-vinylpyridine (4-VP) in scCO2 with N, N/-methylenebisacrylamide as cross-linker. The effects of the reaction pressure, cross-linker ratio, initiator concentration, and reaction time were investigated. It was found that under the condition of 14 MPa and 70°C the cross-linked P4-VP microparticles were generated in scCO2, in yield of 80%, using higher cross-linker concentrations.(3) Furthermore, Molecularly Imprinted Polymers (MIPs) for (S)-naproxen were prepared in supercritical carbon dioxide. In the present work, (S)-naproxen was used as a model template, 4-vinylpyridine as a functional monomer, and Ethylene Dimethacrylate as a crosslinker. Compared with the nonimprinted polymers (NIPs), the MIPs displayed much higher (S)-naproxen uptake in acetonitrile. Scatchard analysis shows that two classes of binding sites were formed in the MIPs in the concentrations range studied. The calculated dissociation constant Kd1 and the apparent maximum binding capacities Qmax1 for the high affinity sites are 0.50 mmol L-1 and 25.5μmol g-1, while Kd2 and Qmax2 for the low affinity sites are 5.3 mmol L-1 and 82.2μmol g-1, respectively.更多还原