【作者】 陆剑燕；

【导师】 陈明清；

【作者基本信息】 江南大学 ， 材料学， 2008， 硕士

【摘要】 本文首先研究了甲基丙烯酸叔丁酯的原子转移自由基聚合(ATRP)的特点。以对氯甲基苯乙烯(CMSt)为引发剂,联二吡啶(2, 2’-bpy)或N,N,N′,N″,N″-五甲基二亚乙基三胺为配位剂,在氯化亚铜(CuCl)的催化作用下,使甲基丙烯酸叔丁酯(tBMA)进行本体聚合。用凝胶渗透色谱(GPC)跟踪聚合物的相对分子质量变化,发现不同配位剂对聚合反应速率有明显的影响,比较了两种不同体系下的反应规律。通过改变引发剂与单体的摩尔配比(1:25, 1: 50, 1: 100和1: 150),可将聚甲基丙烯酸叔丁酯(St-PtBMA)的相对分子质量控制在2×103～1.8×104范围内,保持其相对分子质量分布≦1.31,并成功得到了线性的动力学曲线,发现此聚合反应的速率方程符合ATRP一级动力学行为。同时用傅立叶红外光谱(FTIR)、核磁共振氢谱(1H-NMR)对产物的结构进行了表征,结果表明所得聚合物St-PtBMA的结构明确,为目标产物。将所合成的聚甲基丙烯酸叔丁酯(St-PtBMA)大分子单体在室温下进行定向水解,得到了亲水性聚甲基丙烯酸大分子单体(St-PMAA)。用傅立叶红外光谱(FTIR)对产物的结构进行了表征,结果表明所得聚合物St-PMAA的结构明确,为目标产物。将所合成的St-PMAA大分子单体在乙醇和水的混合介质中与苯乙烯进行分散共聚反应,制得了聚苯乙烯接枝PMAA(PSt-g-PMAA)共聚微球,初步考察了该类大分子单体在分散共聚中的作用。通过扫描电子显微镜、Zeta电位及粒径分析仪对微球粒径与形态进行了表征;同时探讨了多种聚合反应条件(介质的极性、PMAA大分子单体的浓度和反应温度)对共聚微球粒径的影响,发现通过改变共聚反应条件可有效地将微球的直径控制在340-1200nm的范围内;并发现该PSt-g-PMAA微球在分散状态下对pH的变化有明显的响应性,可望在药物负载和蛋白质吸附分离等方面得到应用。更多还原

【Abstract】 In this paper, bulk atom transfer radical polymerization (ATRP) of tert- butylmethacrylate (tBMA) was studied.P-chloromethylstyrene (CMSt) was selected as an initiator, 2, 2’-bipyridyl(bpy) or N,N,N′,N″,N″-Penta-methyldiethylenetriamine (PMDETA) as a ligand, with CuCl as catalyst. Poly(tert-butyl methacrylate) with a halogen atom end group St-PtBMA was synthesized by bulk ATRP at 80 oC. It was found that ligand could clearly affect polymerization rate of tBMA monomer based on measurement of molecular weight of St-PtBMA under different ligand systems by using gel permeation chromatography (GPC). The polymerization regulations under different system were compared. The number average molecular weight (Mn) of St-PtBMA could be controlled in a range from 2×103 to 1.8×104 g/mol by varying the ratio of monomer to initiator (1: 25, 1: 50, 1: 100 and 1: 150), and distribution of molecular weight (Mw/Mn) kept lower than 1.31. The 1H-NMR chemical shifts in parts per million (ppm) were recorded from 0.00 ppm using tetramethylsilane as an internal reference. It was found that obtained PtBMA had a specific structure.Then hydrophilic poly(methacrylic acid) macromonomer (St-PMAA) was obtained through hydrolysis of St-PtBMA in CH2Cl2 in the presence of trifluoroacetic acid (TFA).Further more, poly(methacrylic acid) (St-PMAA) macromonomer was selected as reaction stabilizer to prepare St-PMAA grafted polystyrene (PSt) microspheres (PSt-g-PMAA). The morphology and particle size of the microspheres were studied by using scanning electron microscopy (SEM) and Zetasizer Nano instruments. The effects of polymerization reaction parameters such as media polarity, concentration of St-PMAA macromonomer and polymerization temperature on the particle size of the PSt-g-PMAA microspheres were investigated. It was shown that the average size of the forming microspheres ranges from 340 to 1200nm by varying those experimental parameters. The PMAA chain on the surface of PSt-g-PMAA microspheres was determined based on the results of Zeta data. Therefore, this kind of graft copolymer microspheres will be expected to get some applications in drug carriers and protein adsorption/separation for its pH response.更多还原