【作者】 石奇；

【导师】 吕兴强；

【作者基本信息】 西北大学 ， 化学工程， 2013， 博士

【摘要】 脂肪族聚酯类高分子材料作为生物可降解材料的主要代表之一,因具有较好的力学性能,生物相容性,易加工等特点,在医用高分子材料、医药等领域有着巨大的应用潜力。聚酯合成中具备优良性能催化剂的开发一直是发展聚酯行业的重要突破之一本文合成了1个单边希夫碱-锌配合物和7个不对称双边希夫碱-锌配合物,并通过元素分析、X-射线单晶衍射、X-射线粉末衍射、核磁共振、紫外光谱、红外光谱和热重分析等对其结构表征：以开发的上述配合物为催化剂,探讨了其催化丙交酯(LA)的均聚、马来酸酐(MA)与氧化环己烯(CHO)的共聚行为,并探索性地尝试了其对L-LA与MA共聚、L-LA与CHO共聚研究；利用凝胶渗透色谱测定了所有聚合物的分子量(Mn)及分子量分布(PDI),利用红外光谱、核磁共振氢谱对其微观结构进行了表征,并利用热重分析对聚合物的稳定性进行了评价；在催化聚合过程中,重点剖析了催化剂结构与聚合效果之间的对应关系,并用筛选的性能优异催化剂考察了单体与催化剂的比例、助催化剂、聚合反应时间、聚合反应温度等对聚合效果的影响,为不对称双希夫碱金属催化剂催化制备生物可降解脂肪族聚酯材料提供新思路。首先,进行1-苯基-3-甲基-4-苯甲酰基-5-吡唑酮(PMBP)与邻苯二胺的单侧-NH2的选择性酮胺缩合,合成了希夫碱前驱体L；并选用具有生物相容性的锌金属离子配位,合成1个单边希夫碱-锌LZn催化剂；再通过金属锌离子的模板效应,利用希夫碱前驱体L与系列醛进一步自组装,开发出具有无毒潜质,结构稳定的7个不对称双边希夫碱-锌LZn-1～LZn-7催化剂,其中LZn-1～LZn-5为单核结构,LZn-7为三核结构。其次,对LZn,LZn-1～LZn-6共7个催化剂催化LA(L-及L,D-)熔融均聚的聚合效果进行了研究。结果表明：该系列催化剂相比催化LD-LA而言,在催化L-LA开环均聚时具有较好的催化活性(0.650×103～4.749×103g·mol-1h-1并探索出性能较好(催化活性为4.160×103g·mol-1h-1,聚乳酸分子量M。为4.298×103g·mol-1,分子量分布PDI为1.19)的LZn-3实现L-丙交酯开环聚合的优化工艺条件为：单体与催化剂比例为1000：1,聚合反应时间为24h,聚合反应温度为160℃。再次,对LZn,LZn-1～LZn-7共8个催化剂分别在4-二甲氨基毗啶(DMAP)协同下参与催化L-LA与MA熔融共聚效果进行了研究。结果表明：该系列催化剂能够实现L-LA与MA共聚并表现出中等催化活性(0.429×103～1.641×103g·mol-1h-1)。对筛选出的LZn-3催化剂,考察其在不同催化条件下的共聚表现有：当单体与催化剂比例为250：250：1：1,反应时间24h,反应温度130℃,与DMAP配伍时有较好的聚合效果(催化活性为2.880×103g·mol-1h-1,共聚物P(LLA-MA)分子量Mn为1.023×104g·mol-1,分子量分布PDI为1.50)。然后,对LZn,LZn-1～LZn-7共8个催化剂分别在DMAP协同下参与催化L-LA与CHO熔融共聚效果进行了研究。结果表明：该系列催化剂能够实现L-LA与CHO共聚并表现出中等催化活性(0.265×103～0.919×103g·mol-1h-1)。综合考察LZn-3在不同催化条件下的共聚表现有：当单体与催化剂比例为250：250：1：1,聚合反应时间为24h,与DMAP配伍时有较好的聚合效果(催化剂的催化活性为0.913×103g·mol-1h-1,共聚物P(LLA-CHO)分子量Mn为2.404×103g·mol-1,分子量分布PDI为1.07)。另外,对LZn,LZn-1～LZn-7共8个催化剂分别在DMAP协同下参与MA与CHO熔融、溶液共聚进行了研究。结果表明：该系列催化剂能够实现MA与CHO熔融、溶液共聚并表现出较高的催化活性(0.52×103～6.57×103g·-mol-1h-1),且都能得到相同数量级(103-104)的共聚物。对筛选出的LZn-3催化剂,考察其在不同催化条件下的共聚表现有：当单体与催化剂比例为250：250：1：1,熔融聚合时间150min,反应温度110℃,与DMAP配伍时有较好的聚合效果(催化活性为6.10×103g·mol-1h-1,共聚物P(MA-CHO)分子量Mn为1.656×104g·mol-1,分子量分布PDI为1.66)。考察LZn-7在不同催化条件下的聚合表现有：当单体与催化剂比例为150：150：1：1,熔融聚合时间150min,聚合反应温度110℃,与DMAP配伍时有较好的聚合效果(催化活性为3.22×103g·mol-1h-1,共聚物P(MA-CHO)分子量Mn为1.403×104g·mol-1,分子量分布PDI为1.17)。最后,综合LZn,LZn-1～LZn-7共8个催化剂在四个不同聚合体系的催化表现有：该系列催化剂能够实现催化L-LA开环均聚,L-LA与MA共聚,L-LA与CHO共聚,MA与CHO共聚；催化剂的催化效果与其结构以及取代基团的空间效应和电子效应有重要关系,不对称双希夫碱锌比单边希夫碱锌催化效果好,三核催化剂比相应单核催化剂具有更好的催化能力；具有拉电子取代基和大位阻取代基结构的催化剂表现出较好的催化行为。更多还原

【Abstract】 Aliphatic polyesters, as the most typical representative of the variety of biodegradable polymers known, had become increasingly important in the development of biomedical polymer materials and drug delivery systems due to their characteristic properties of high mechanical strength, biocompatibility and easily processed ability. As the key to synthesis, the development of catalysts was one of the important breakthroughs in aliphatic polyester industry.In this thesis, one Zn(Ⅱ) unilateral Schiff-base complex and seven Zn(Ⅱ) asymmetric bis-Schiff-base complexes were obtained, respectively. They were characterized by element analysis (EA), X-ray single-crystal diffraction (XRD), powder X-ray diffraction (PXRD), nuclear magnetic resonance spectrum (NMR), ultraviolet-visible absorption spectrum (UV-Vis), infrared spectrum (FT-IR) and thermo-gravimetric analysis (TGA). Moreover, all the eight complexes were used as catalysts for the ring-opening polymerization of lactide as well as the copolymerization of L-lactide (LLA) and maleic anhydride (MA), LLA and cyclohexene oxide (CHO) or MA and CHO. The molecular weight size (Mn or Mw) and the molecular weight distribution (PDI=Mw/Mn) of the obtained polymers were determined by gel permeation chromatography (GPC). In addition, the microstructures and properties of polymers were characterized by the FT-IR,1H NMR and TGA. During the process of polymerization, the study on the corresponding relationship between catalysts structure and the polymerization behavior was focused. The catalysts with excellent performance were selected to investigate the effects of the molar ratio of monomer and catalyst, co-catalyst, polymerization time and polymerization temperature on detailed polymerization.Firstly, based on the unilateral Schiff-base ligand L synthesized from the selective condensation reaction of1-Phenyl-3-methyl-4-benzoyl-2-pyrazolin-5-one (PMBP) and one-NH2of1,2-diaminobenzene, the zinc(Ⅱ) unilateral Schiff-base complex LZn was obtained by the coordination of Zn ion with two ligands L. Furthermore, utilizing the Zn-templating effect, seven asymmetric zinc(Ⅱ) bis-Schiff-based complexes (LZn-1～LZn-7) were obtained from the condensation reaction of L and one of aldehyde derivatives (salicylaldehyde,5-bromo-2-hydroxy-benzaldehyde,3,5-dibromo-2-hydroxy-benzal-dehyde, o-vanillin,5-bro-mo-3-methoxy-2-hydroxy-benzaldehyde and3,5-ditert-butyl-2-hydroxybenzaldehyde). The X-ray single crystal diffraction determinations showed that five (LZn-1～LZn-5) of the complexes were monomers and one (LZn-7) of complexes had homo-trinuclear framework.Secondly, the bulk polymerization behaviors of LA (LLA and L,D-LA) were studied in detail by using complexes LZn and LZn-1～LZn-6as the catalysts. The results showed that all the zinc(II) catalysts had a relatively higher catalytic activity (0.650-4.749×103g·mol-1h-1) for the polymerization of LLA in contrast to that of L,D-LA. On the condition of better catalytic behaviors (Catalytic activity of4.160×103g·mol-h-1, Mn of4.298×103g·mol-1and PDI of1.19) from the selected catalyst LZn-3, the controllable polymerization process was based on the molar ratio of monomer and catalyst of1000:1, the polymerization time of24h and the polymerization temperature of160℃.Thirdly, the bulk copolymerization behaviors of LLA and MA were studied in detail by using the eight complexes LZn and LZn-1-LZn-7as the catalysts in presence of4-dimethylaminopyridine (DMAP). The results showed that the effective copolymerization of LLA and MA was realized with the moderate catalytic activity (0.429～1.641×103g·mol-1h-1). Using the selected LZn-3as the suitable catalyst from the copolymerization condition of the molar ratio of LLA, MA, catalyst and DMAP of250:250:1:1, the reaction time of24h and the polymerization temperature of130℃, the relatively better catalytic behaviors were obtained, where the catalytic activity was up to2.880×103g·mol-1h-1, the Mn of the P(LLA-MA) was1.023×104g·mol-1and PDI was1.50.The bulk copolymerization behaviors of LLA and CHO were also studied in detail by using the eight complexes LZn and LZn-l-LZn-7as the catalysts in presence of DMAP. The results showed that the effective copolymerization of LLA and CHO was realized with the moderate catalytic activity (0.265×103～0.919×103g·mol-1h-1). Using the selected LZn-3as the suitable catalyst from the copolymerization condition of the molar ratio of LLA, CHO, catalyst and DMAP of250:250:1:1, the reaction time of24h and the polymerization temperature of115℃, the relatively better catalytic behaviors were obtained, where the catalytic activity was0.913×103g·mol-1h-1, the Mn of the P(LLA-CHO) was2.404×103g·mol-1and PDI was1.07.Fourthly, the copolymerization behaviors of MA and CHO in both bulk and in solvent were studied in detail by using the eight complexes LZn and LZn-1-LZn-7as the catalysts in presence of DMAP. The results showed that the effective copolymerization of MA and CHO was realized with the excellent catalytic activity (0.52×103～6.57×103g·mol-1h-1). Using the selected LZn-3as the suitable catalyst from the copolymerization condition of the molar ratio of MA, CHO, catalyst and DMAP of250:250:1:1, the reaction time of150min and the polymerization temperature of110℃in bulk, the relatively better catalytic behaviors were obtained, where the catalytic activity was6.10×103g·mol-1h-1, the Mn of the P(MA-CHO) was1.656×104g·mol-1and the PDI was1.66. Using the selected LZn-7as the suitable catalyst from the copolymerization condition of the molar ratio of MA, CHO, catalyst and DMAP of150:150:1:1, the reaction time of150min and the polymerization temperature of110℃in bulk, the relatively better catalytic behaviors were obtained, where the catalytic activity was3.22×103g·mol-1, the Mn of the P(MA-CHO) was1.403×104g·mol-1and the PDI was1.17.Finally, all the performances of the series zinc(Ⅱ) catalysts demonstrated that it could achieve the polymerization of LLA, the co-polymerization of LLA and MA, of LLA and CHO and of MA and CHO. The effect of polymerization was clearly influenced by the structure of the catalyst, especially the steric effects and the electronic effects of the catalysts. The asymmetric zinc(Ⅱ) bis-schiff-based catalysts had better catalytic effect than the zinc(Ⅱ) unilateral schiff based ones. The zinc(Ⅱ) catalyst with trinuclear structure had better catalytic effect than the zinc(Ⅱ) with mononuclear ones. The catalyst with the withdrawing substituent groups or having a large steric hindrance groups showed superior catalytic effect.更多还原