Short-Range Order in Polymer Liquids and Glasses

本论文的前期研究表明，在确定聚合物玻璃的性能时，近程序的重要性。为了证实这一点并获得有关聚合物液体和玻璃中的短程秩序的进一步信息，将采用以下三种方法。首先，研究人员将对受不同机械和热历史影响的玻璃状聚合物样品进行x射线散射测量。他将运用他早期发展的中间角散射测量技术和能量色散x射线衍射技术。其次，他将用四种类型的聚苯乙烯进行中子散射测量——普通聚苯乙烯、过氘聚苯乙烯、仅在脂肪基上氘化的聚苯乙烯和仅在芳香环上氘化的聚苯乙烯。这一结果可以提供有关当前短距离秩序的原子对类型的更详细信息。第三，将对实际体块聚苯乙烯模型进行分子动力学模拟，并对模拟结果进行分析，以帮助解释x射线和中子散射结果。

The prior study by the principal investgator indicates the importance of short-range order in determining the properties of polymer glasses. To confirm this and obtain further information about the short-range order in polymer liquids and glasses, the following three lines of approach will be pursued. First, the investgator will perform X-ray scattering measurements on glassy polymer samples subject to different mechanical and thermal histories. He will empoly the technique of the intermediate- angle scattering measurement he had developed earlier, as well as the technique of energy-dispersive X-ray diffraction. Second, he will perform neutron-scattering measurement with four types of polystyrene - - ordinary polystyrene, perdeuteriated polystyrene, polystyrene deuteriated on aliphatic groups only, and polystyrene deuteriated on aromatic rings only. The results can provide more detailed information about the types of atomic pairs responsible for the short-rang order present. Third, molecular dynamics simulation of models of realistic bulk polystyrene will be performed and the result will be analyzed to aid the interpretation of the X-ray and neutron-scattering results.