Relaxation Studies on Glassy Polymers

对玻璃聚合物的动力学和弛豫行为进行了研究。在实验上，现代固体高分辨率核磁共振方法将与最近发展的膨胀测量技术相结合，作为玻璃聚合物中分子运动和链式堆积效应的探针。特别是，研究者将在高二氧化碳压力下对聚碳酸酯进行所谓的CPMAS NMR实验，以获得吸收气体分子对分子运动和链堆积的影响的信息。研究者还将使用多重量子核磁共振来获得有关玻璃中聚合物相关运动程度的新信息，并将核磁共振实验与宏观性质（例如动态机械损失）联系起来。理论上，研究者将使用计算机模拟、现象学模型构建和统计力学相结合的方法来理解玻璃聚合物中的弛豫过程。

Studies are conducted on the dynamics and relaxation behavior of glassy polymers. Experimentally, the methods of modern high-resolution NMR of solids will be used in conjunction with a recently developed dilatometry technique as a probe of the molecular motions and chain-packing effects in glassy polymers. In particular, the investigator will perform so-called CPMAS NMR experiments on polycarbonates under high carbon dioxide pressure to obtain information on the effects of absorbed gas molecules on the molecular motions and chain packing. The investigator will also use multiple quantum NMR to obtain new information about the extent of correlated motion of the polymer in the glass and to correlate the NMR experiments with macroscopic properties, e.g. dynamic mechanical loss. Theoretically, the investigator will use a combination of computer simulations, phenomenological model building, and statistical mechanics to understand the relaxation processes in glassy polymers.