Dynamic Processes in Glassy Polymers

这项研究是一个实验核磁共振研究小组和一个理论化学研究小组合作进行的，目的是研究玻璃态聚合物的动力学。实验小组将把现有的现代固体核磁共振技术与新的实验(旋转回波、双共振C-13-F-19核磁共振和旋转回波去相H-1核磁共振)相结合，研究聚碳酸酯和聚碳酸酯类塑料中主链苯环180度翻转的动力学。这些系统将在各种物理条件下进行研究，包括高外部静水压力。链将在整体和聚合物-聚合物界面上进行检查。苯环翻转之所以令人感兴趣，是因为它们监测固体的缓慢密度波动，这与韧性等物理性质有关。为了更详细地了解这些密度波动，将进行一组使用广义朗之万动力学模拟技术的并行计算实验。这种计算机模拟方法是专门为模拟玻璃固体中的慢动作而开发的。

This research is a collaborative effort between an experimental NMR research group and a theoretical chemistry research group to investigate the dynamics of glassy polymers. The experimental group will combine existing techniques of modern solids NMR with new experiments (rotational-echo, double-resonance C-13--F-19 NMR and rotational-echo dephasing H-1 NMR) to investigate the dynamics of 180o flips of the main-chain phenyl rings in polycarbonates and polycarbonate-like plastics. These systems will be investigated under a variety of physical conditions including high external hydrostatic pressure. Chains will be examined in bulk and at polymer-polymer interfaces. Phenyl ring flips are of interest because they monitor the slow density fluctuations of the solid, which are related to physical properties such as toughness. To understand these density fluctuations in detail, a parallel set of computational experiments using a Generalized Langevin Dynamics simulation technique will be undertaken. This method of computer simulation has been specifically developed to allow the simulation of slow motions in a glassy solid.