【作者】 王文浩；

【导师】 徐祖顺；

【作者基本信息】 湖北大学 ， 高分子化学与物理， 2011， 硕士

【摘要】 聚合物纳米粒子因其特殊的结构,优良的性能,受到了研究人员的极大关注,特别是在医药生物领域。但是在诸如生物医药等领域应用时,往往会严格要求其粒径的大小及单分散性,而传统的制备方法在制备单分散纳米级微球方面则显出了不足,这就对制备方法提出了更高的要求。可逆断裂-加成链转移聚合(RAFT)、单电子转移自由基聚合(SET-LRP)和乳液原子转移自由基聚合(乳液ATRP)自诞生以来,因广泛的单体适用范围,对聚合体系良好的控制性以及可合成多种特殊结构聚合物的特性引起了高分子化学界的极大兴趣。特别是近几年来,随着部分RAFT试剂的工业化以及AGET ATRP和eATRP体系的相继出现,大大促进了这些技术的发展,在一定程度上将这些可控/活性自由基聚合技术带出了实验室,而不仅仅限于理论研究。树枝状-星型聚合物本身就具有纳米级的结构,并且具有规整的体型结构、丰富的末端官能基团,一些树枝状-星型聚合物还拥有天然的、可用于包埋小分子的微囊和微腔,因而在载药、靶向等方面具有广阔应用前景。但是树枝状大分子的成本问题一直没得到解决,在这种情况下,拥有大部分大分子性能并且成本更加低廉的星型小分子便成为最理想的替代物质。在本课题中,我们使用酰卤改性季戊四醇制备适用于ATRP的星型小分子引发剂,然后采用先聚合后配位的方式制备稀土荧光微球。首先,通过乳液原子转移自由基聚合制备星型结构的聚甲基丙烯酸甲酯纳米微球,成功制备出粒径在100 nm以下且单分散性较好的纳米粒子。随后,使用红外、核磁、GPC、PCS、TEM等仪器分别对其结构、分子量、形貌进行表征。最后,将稀土离子在合适的条件下与聚合物进行配位,研究其荧光性能,并发现在同等稀土添加量时,星型聚合物的荧光性能强于同剂量单体聚合得到的线形聚合物。为得到更理想的荧光微球,进一步提高其荧光性能,在随后的研究中我们尝试引入配位效果更佳的功能性单体马来酸酐。马来酸酐水解后会产生双酮基的结构,能与稀土离子形成更稳定的螯合结构,因此会有更好的荧光性能。通过该功能单体的引入,我们期望通过RAFT聚合的方式制备具有更优良荧光强度的星型马来酸酐共聚物。制备的第一步需要先合成星型的RAFT试剂,本课题采用较成熟的CS2方法先合成出含双二硫酯的RAFT试剂,后通过两种不同的途径合成星型RAFT试剂,并用核磁对其结构进行表征。通过核磁表征发现含双二硫酯的RAFT试剂合成成功,但星型RAFT试剂的合成结果不够明确。并且因时间原因,尚未探索出理想的合成条件。更多还原

【Abstract】 Because of their special structure and excellent performance, nanoparticles have attacted great concern of researchers, particularly in the pharmaceutical and biotech fields. However, in areas such as biomedical application often strictly requires the diameter of the particle size and monodispersity, and the traditional synthetical methods usually have some difficulties in the preparing monodisperse nano-sized particles., while more advanced technique were required.Since their inception, reversible addition-fragmentation chain transfer polymerization (RAFT), single electron transfer radical polymerization (SET-LRP) and the emulsion atom transfer radical polymerization (emulsion ATRP) also attracted great interest in polymer science, due to the usage of wide range of monomers, controlled/living charateristic and synthesis of a variety of special structure as well as star-polymers, comb polymers. Especially in recent years, as part of the RAFT agents have been industrialized and the discoveries of AGET ATRP and eATRP system have greatly promoted the development of these technologies. To a certain extent, these breakthroughs have brought controlled/living radical polymerization technique out of the laboratory, not just theorization.Dendritic-star polymer itself has a nano-structure, a clear body structure and the great amount of end functional groups. A number of dendrimer-star polymer also has a natural, small microcapsules and micro-cavity that can be used for embedding minimolecules such as the drug and targeting drugs, for the purpose of these reason,they has broad application prospects. However, the cost of dendrimers has not been resolved, in this case, with most properties of these dendrimers and less costly, small star molecules have become the best alternative substances.In this issue, star minimolecule acyl halides were synthesis by modification of pentaerythritol as ATRP initiator, and then the polymerization were implemented for the preparation of rare earth complexes fluorescent microspheres. Firstly, star-like PMMA nanoparticles with diameter smaller than 100nm and monodispersed were successfully prepared by emulsion atom transfer radical polymerization. Subsequently, the infrared, NMR, GPC, PCS, TEM and other equipments were used to characterize its structure, molecular weight and morphology characterization. Finally, the rare earth solvent with convenient concentration was added for coordination with the polymer for the studying of the fluorescent properties of rare earth complex by comparing with the linear polymer with the same amount of rare earth, the fluorescence properties of star polymer is stronger than the linear polymer with same dose of monomers.In order to get better fluorescent microspheres, and enhance its fluorescent properties, in the subsequent study, we attempt to introduce a better coordinated functional monomer maleic anhydride. Hydrolysis of maleic anhydride will produce double-keto structure, which can form more stable chelate structure with the rare earth; there will be a better fluorescence. By the introduction of the functional monomer, we have to look forward a new technique for the preparing of star maleic anhydride copolymer, which is the RAFT polymerization. The first step was to synthesis star-shaped RAFT agent, a more mature approach with which started by CS2 was conducted to synthesize the double disulfide ester RAFT agent, then star-RAFT agents were synthesiszed by two different pathways and the structures were characterized by NMR. The RAFT agent containing two-disulfide ester was successfully synthesized, but the results of the star-shaped RAFT agent were not clear. What’s more, the ideal condition was still unknown for the purpose of time limitied.更多还原