混合溶剂结构与高分子溶解能力的关系：从共混不互溶现象说起

项目名称： 混合溶剂结构与高分子溶解能力的关系：从共混不互溶现象说起

项目编号： No.21474119

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 程贺

作者单位： 中国科学院高能物理研究所

项目金额： 87万元

中文摘要： 通过联用小角中子散射、动静态光散射、核磁共振、傅里叶红外技术，我们重新观察混合溶剂结构对高分子溶解行为的影响，辨识高分子-溶剂之间直接相互作用与间接相互作用在高分子溶解过程中的贡献。混合溶剂中存在多尺度结构，溶剂分子既可以通过诸如氢键、范德华力之类的相互作用直接作用于高分子，又能通过多尺度结构形成新的复合物间接作用于高分子。我们通过使用小角中子散射的衬度匹配方法，确定哪种作用对高分子的溶解起主导作用，从而将混合溶剂的微观多尺度结构与高分子的宏观溶解行为联系起来，逐步解决理论与实际生产过程的难题：探索共混不互溶现象的本质，研究混合溶剂结构与高分子溶液相转变过程的关系，从而建立高分子溶解的微观模型，指导纤维素加工过程中绿色溶剂的选择。

中文关键词： 小角中子散射；光散射；多尺度结构；共混不互溶；相转变

英文摘要： The role of structures of mixed solvent on polymer solubility are studied by a combination of small angle neutron scattering (SANS), dynamic & static laser light scattering (DLS & SLS), nuclear magnetic resonance (NMR) and fourier transform infrared spectroscopy (FTIR). There are multi-scale structures in mixed solvent. The solvent molecules may interact directly with polymer via interactions (direct interaction) such as hydrogen bonding, van der waals force, et al., and they may also affect polymer solubility indirectly (indirect interaction) by forming a complex, who can be considered as a new solvent. Because those two effects always co-exist in polymer dissolution process, contrast matching techniques in SANS must be involved to distinguish their contributions. Then the micro-structures of mixed solvent can be connected with polymer dissolution, and a general theoretical framework can be established. According to the theoretical framework, some physical debates can be clarified, e.g., the origin of co-nonsolvency, and the relationship between structure of mixed solvent and phase separation process in polymer solution. Moreover, the framework is essential to optimize the solvent selection of natural cellulose.

英文关键词： small angle neutron scattering;laser light scattering;multi-scale structure;co-nonsolvency;phase transition