利用核磁共振技术研究嵌段共聚物在复杂体系中的相互作用
文献类型：学位论文
| 作者 | 宋寒 |
| 学位类别 | 硕士 |
| 答辩日期 | 2009-06-04 |
| 授予单位 | 中国科学院过程工程研究所 |
| 授予地点 | 过程工程研究所 |
| 导师 | 刘会洲 |
| 关键词 | PEO-PPO-PEO嵌段共聚物 核磁共振 胶团行为 化学微环境 相互作用 |
| 其他题名 | Study on the Interaction of PEO-PPO-PEO Block Copolymer in the Complex Systems by Nuclear Magnetic Resonance Technology |
| 学位专业 | 化学工艺 |
| 中文摘要 | 聚氧乙烯-聚氧丙烯-聚氧乙烯（PEO-PPO-PEO）嵌段共聚物是一类非离子型高分子表面活性剂。由于PEO和PPO链段的长短在合成时能够控制，该类嵌段共聚物可以衍生出多种具有不同PPO与PEO相对含量和物理化学性质的分子，使其广泛应用于诸多工业领域，如有机物增溶、药物控制释放、生物大分子分离以及介孔材料制备等方面。而近些年来在越来越多的实际应用中，嵌段共聚物都需要在与其他一种或几种物质组成的复杂体系中发挥作用。因此，对PEO-PPO-PEO嵌段共聚物在复杂体系中的胶团行为、化学微环境等相互作用进行研究具有重要的理论和实际意义。本研究的目的在于从分子水平揭示PEO-PPO-PEO嵌段共聚物在复杂体系中的胶团行为、体系中的相互作用及化学微环境变化，以探索PEO-PPO-PEO嵌段共聚物在复杂体系中的应用。 本文主要应用核磁共振波谱（NMR）技术研究了PEO-PPO-PEO嵌段共聚物在多种复杂体系中的相互作用，主要涉及嵌段共聚物与非离子型疏水性表面活性剂的复杂体系，二元混合嵌段共聚物的复杂体系以及嵌段共聚物与离子液体的复杂体系中的胶团行为、体系中的相互作用及化学微环境变化的研究。研究结果为PEOPPOPEO嵌段共聚物在复杂体系中的应用提供了科学依据。研究内容主要包括以下三个方面： 1．对一系列的PEO-PPO-PEO型嵌段共聚物，F88、P84和P123与不同浓度的Surfynol® 104组成的混合水体系进行了研究。发现S104的加入促进了胶团形成，明显降低了共聚物的临界胶团温度，并且随着S104浓度的增大临界胶团温度降低得更多。S104增强了PEO链段的水化程度，而对于PPO链段，在嵌段共聚物胶团形成之前，在一定程度上增强了其水化程度，而在胶团形成之后则明显降低了其水化程度。S104的作用程度与嵌段共聚物PEO/PPO比有关。 2．对一系列PEO-PPO-PEO嵌段共聚物二元混合物进行实验，研究混合胶团的形成情况以及化学微环境的变化。研究发现，当PPO链段数目接近时(＜15)，二元混合嵌段共聚物随着温度升高能够生成混合胶团。当PPO链段数相差较大(＞15)时，混合胶团不能生成。这是因为PPO链段数目接近时，在混合胶团形成过程中二种嵌段共聚物的PPO链段容易发生相互作用，共同形成混合胶团内核，进而生成了混合胶团，而PPO链段长度相差较大时，二元混合嵌段共聚物的PPO链段不容易发生相互作用，二者先后生成胶团。同时，对于二元混合嵌段共聚物CMT值的研究证明了上述结论。 3．研究了不同水溶性质的[Bmim]型离子液体对不同PPO与PEO链段组成嵌段共聚物，F88、P85和P123的化学微环境，相互作用以及胶团行为的影响。研究发现，离子液体的加入，都能够使得嵌段共聚物的PEO 链段和PPO 链段的去水化程度增强；亲水性离子液体对PEO链段和PPO链段的去水化程度增强作用随着浓度的增大而增大。疏水性离子液体的加入降低了嵌段共聚物的CMT，并且随着嵌段共聚物亲水性的增强，疏水性离子液体对于CMT降低的作用增强。亲水性离子液体降低了疏水性较强P85和P123的CMT值，却提高了亲水性较强F88的CMT，并且这些作用也随着亲水性离子液体的浓度增大而增强。 |
| 英文摘要 | PEO-PPO-PEO triblock copolymers are a class of nonionic macromolecular surfactants. The molecular characteristics (PPO/PEO ratio and molecular mass) of the copolymers are varied during the synthesis, which derives various molecules with different contents of PEO and PPO and physiochemical properties. Thesee copolymers are applied in different industrial fields, such as organic solubilizing, controlled drug delivery, bioseparation, and synthesis of mesoporous materials. Recently, in more practiacal applications, PEO-PPO-PEO block copolymers are applied in the complex systems with other components. Therefore, the investigations of micellar behavior and chemical microenvironment of PEO-PPO-PEO block copolymers in the complex systems have attracted considerable attention in both basic study and practical application. The purpose of this research work is to molecularly reveal the micellar behavior, interactions of components and variation of microenvironment of PEO-PPO-PEO block copolymer in aqueous mixed systems, trying to find their application in complex systems. The micellar behaviors, interactions of system components and changes of chemical microenvironment in the complex systems of PEO-PPO-PEO block copolymer and nonionic hydrophobic surfactant, binary PEO-PPO-PEO mixtures, PEO-PPO-PEO block copolymers and ionic liquids were investigated by nuclear magnetic resonance (NMR) technology. The main results were as follows: 1. A series of PEO-PPO-PEO triblock copolymers, Pluronic F88, P84 and P123, in different Surfynol® 104 (S104) aqueous solutions were studied. The addition of S104 into copolymer solutions promoted the micellization process and markedly decreased the critical micellization temperature (CMT) of copolymers. The more S104 was added into solutions, the more CMT decreased. It was found that S104 caused different effects on the chemical shifts of Pluronic copolymer segments. For PEO segments, the addition of S104 enhanced their hydration. For PPO segments, S104 slightly increased the hydration of PPO segments before the micelle formation, and remarkably decreased the hydration of PPO segments after micellization. The effects of S104 on the CMT and chemical shifts of copolymers were related to their PEO/PPO ratios. 2. A series of binary mixtures of Pluronic block copolymers in aqueous solution were studied to investigate the micelle formation and microenvironment of mixtures. It was found that the mixed micelles of binary mixtures formed when the difference between PPO segment numbers of two copolymers was smaller than 15. When the difference was over 15, there existed no mixed micelle. The reason was that when PPO segment numbers were close, PPO segments of two copolymers interacted with each other to form the mixed hydrophobic cores of micelles, further, the mixed micelles formed. However, when the difference between PPO segments was large, PPO segments did not interact with each other, two copolymers formed individual micelles respectively. The study of CMT of binary mixtures proved this conclusion. 3. The mixed systems of Pluronic copolymers (F88, P85 and P123) and [Bmim] ionic liquids in aqueous solutions were studied to investigate microenvironment, interaction and micellar behavior. It was concluded that the addition of ionic liquids enhanced the dehydration of PEO and PPO segments, and the enhancement of hydrophilic ionic liquid in dehydration of segments increased as its concentration increased. The addition of hydrophobic ionic liquids decreased CMT of copolymers, and this effect was strengthened as the hydrophilicity of copolymer increased. Hydrophilic ionic liquids decreased CMT of hydrophobic copolymers (P85 and P123), but increased CMT of hydrophilic copolymer (F88). This influence on CMT increased with increasing the concentration of hydrophilic ionic liquid. |
| 语种 | 中文 |
| 公开日期 | 2013-09-16 |
| 页码 | 88 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1282]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 宋寒. 利用核磁共振技术研究嵌段共聚物在复杂体系中的相互作用[D]. 过程工程研究所. 中国科学院过程工程研究所. 2009. |
入库方式： OAI收割
来源：过程工程研究所
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