ε-己内酯与聚乙二醇嵌段共聚物合成的研究
发布时间：2018-12-06 10:21
【摘要】：本文合成了4-甲基苯并12-冠-4咪唑卡宾(B12C4imY)和2,3,6,7-四氢-5H-噻唑并[3,2-a]嘧啶(ITU)两种有机催化剂。在聚乙二醇(PEG)作大分子引发剂的条件下,用卡宾催化剂B12C4imY和ITU与卤化镁(MgX2)的共催化剂(ITU/Mg X2)分别催化ε-己内酯(CL)开环聚合,制备了三嵌段共聚物PCL-PEG-PCL。系统地探索了嵌段聚合反应的特征,得到了反应的最佳条件。利用NMR、IR、GPC和DSC测试手段表征了聚合物的结构、分子量及热性能,并推测了可能的聚合机理。在四氢呋喃(THF)溶液中,以PEG为引发剂,B12C4imY催化CL开环聚合,合成了PCL-PEG-PCL三嵌段共聚物。通过对聚合时间、温度、催化剂用量、单体浓度和引发剂用量等条件的研究,得到该共聚反应的最适条件:[M]=3.0 mol/L,[M]/[C]=300,[M]/[I]=200,25℃下,反应40 min,CL的转化率高达96.8%。在此条件下所得聚合物的分子量(Mn)和分子量分布(PDI)分别是:Mn=3.68×104 g/mol,PDI=1.47。1H NMR和IR分析证明了共聚物的结构,推测该反应的机理为“单体-活化”机理。三嵌段共聚物的DSC曲线显示在64.3℃有一个熔融峰。用PEG作为大分子引发剂,将ITU/Mg X2体系用于CL的开环聚合,制备了分子量较高且分子量分布较窄的三嵌段共聚物PCL-PEG-PCL。实验表明ITU/Mg X2体系是催化内酯开环聚合的有效催化剂。用1H NMR,13C NMR,IR,GPC,DSC等分析手段对聚合物的结构与热性能进行了表征与分析。实验得到了以下结论:1.用PEG和ITU/Mg X2催化体系引发CL开环聚合,当[M]=2.0 mol/L,[M]/[C]=80,[M]/[I]=200,30℃下,在THF中反应12 h可以得到Mn为6.6×104 g/mol,PDI为1.43的三嵌段共聚物。2.通过NMR和IR测试手段对PCL-PEG-PCL的结构进行了分析,并推断出聚合反应的机理。GPC测试得到了聚合物的Mn和PDI值,PCL-PEG-PCL的GPC曲线为单峰,与PCL相比,曲线向高分子量方向移动。通过DSC测试方法对PCL、PEG以及PCL-PEG-PCL的热性能进行了对比,研究表明,PEG段的引入使得聚合物的熔融温度和结晶温度都有明显提升。
[Abstract]:Two kinds of organic catalysts, 4-methylbenzo-12-crown-4 imidazole carbene (B12C4imY) and 2H3H3H- tetrahydro-5H-thiazolyl (ITU), have been synthesized in this paper. The ring-opening polymerization of 蔚 -caprolactone (CL) was carried out with carbene catalyst B12C4imY and ITU and magnesium halide (MgX2) co-catalyst (ITU/Mg X2) under polyethylene glycol (PEG) as macromolecular initiator. Triblock copolymer PCL-PEG-PCL. was prepared. The characteristics of block polymerization were systematically explored and the optimum reaction conditions were obtained. The structure, molecular weight and thermal properties of the polymer were characterized by NMR,IR,GPC and DSC, and the possible polymerization mechanism was deduced. PCL-PEG-PCL triblock copolymers were synthesized by ring-opening polymerization of CL catalyzed by B12C4imY in tetrahydrofuran (THF) solution with PEG as initiator. By studying the polymerization time, temperature, amount of catalyst, monomer concentration and initiator dosage, the optimum conditions for the copolymerization were obtained: [M] = 3.0 mol/L, [M] / [C] = 300, [M] / [I] = 200,25 鈩，
本文编号：2365884
[Abstract]:Two kinds of organic catalysts, 4-methylbenzo-12-crown-4 imidazole carbene (B12C4imY) and 2H3H3H- tetrahydro-5H-thiazolyl (ITU), have been synthesized in this paper. The ring-opening polymerization of 蔚 -caprolactone (CL) was carried out with carbene catalyst B12C4imY and ITU and magnesium halide (MgX2) co-catalyst (ITU/Mg X2) under polyethylene glycol (PEG) as macromolecular initiator. Triblock copolymer PCL-PEG-PCL. was prepared. The characteristics of block polymerization were systematically explored and the optimum reaction conditions were obtained. The structure, molecular weight and thermal properties of the polymer were characterized by NMR,IR,GPC and DSC, and the possible polymerization mechanism was deduced. PCL-PEG-PCL triblock copolymers were synthesized by ring-opening polymerization of CL catalyzed by B12C4imY in tetrahydrofuran (THF) solution with PEG as initiator. By studying the polymerization time, temperature, amount of catalyst, monomer concentration and initiator dosage, the optimum conditions for the copolymerization were obtained: [M] = 3.0 mol/L, [M] / [C] = 300, [M] / [I] = 200,25 鈩，
本文编号：2365884
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