高分子玻璃化转变机理的固体NMR研究

玻璃化转变机理一直是高分子科学和凝聚态物理高度关注的交叉前沿领域，由于玻璃化转变是非各态历经，其非均匀动力学演化的时间尺度跨越几个数量级范围，使得高分子玻璃化转变机理研究一直是国际性科学难题。本项目拟通过新颖的多尺度固体NMR技术结合其它实验手段，以典型的非晶态高分子均聚物、共聚物和共混物为研究对象，在不同时空间尺度上阐明高分子玻璃化转变中若干重要的基本科学问题。采用13C分离局域场技术检测高分子链间相互作用及其演化、采用1H自旋扩散技术揭示结构非均匀性的演化、采用偶极调控技术阐明玻璃化转变过程中何时液态高分子链出现以及固态高分子链消失、采用检测超慢运动的NMR技术检测非均匀动力学演化及玻璃化转变起始和终止温度。通过上述多时空尺度的研究，阐明高分子玻璃化转变中非均匀结构与动力学演化的物理图像，揭示玻璃化转变机理。研究工作通过多学科交叉融合，将对高分子物理的发展起到重要的推动作用。

The mechanism of glass transition has always been a frontier research field in polymer science and condensed matter physics. Because glass transition is a non ergodic process, and its time scale of heterogeneous dynamic evolution spans several orders of magnitude, the research on the mechanism of polymer glass transition has always been an international scientific difficult problem. In this project, through novel multi-scale solid-state NMR technique in combination with other experimental techniques, and take typical amorphous homopolymers, copolymers and polymer blends as the research object, several important basic scientific issues in polymer glass transition will be clarified on multiple time and length scales. The 13C separation local field technique is used to detect the interchain interaction and its evolution, the 1H spin diffusion technique is used to reveal the evolution of structural heterogeneity, the dipole interaction-editing technique is used to elucidate when the liquid polymer chains appear and the solid polymer chains disappear upon glass transition, and the NMR technique to detect the ultra-slow motion is used to detect the evolution of heterogeneous dynamics, and the start and end temperatures. Based on the above research, the physical picture of the evolution of heterogeneous structure and dynamics upon glass transition will be clarified, and the mechanism of polymer glass transition could be revealed. Through interdisciplinary integration in this project, our research work will play an important role in promoting the development of polymer physics.