Dynamic Light Scattering Investigations of Segmental Motion and Viscoelasticity in Polymers

聚合物中分段运动和粘弹性的动态光散射研究

• 批准号: 9112993
• 负责人: C. H. Wang
• 金额: $ 28.4万
• 依托单位: University of Nebraska-Lincoln
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-02-15 至 1997-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9112993&HistoricalAwards=false
• 关键词: Dynamic; Light; Scattering; Investigations; Segmental

This study of the dynamics of local segmental motion in polymers will include polymer solutions in semi-dilute and concentrated regions and in miscible polymer blends. The techniques to be used are various types of dynamic light scattering, including photon correlation spectroscopy, Brillouin scattering and holographic grating relaxation. Properties such as dynamic longitudinal and shear compliances, dynamic longitudinal and shear moduli, hyper- sonic velocity and attenuation coefficient, mutual and tracer diffusion coefficients of labeled chains in the semi-dilute or/and concentrated polymer solutions will be investigated. The spectrum will be measured as a function of polymer molecular weight, concentration, scattering wavevector, and solvent qualities. Efforts will be made to relate the dynamic light scattering to the mechanical relaxation spectrum of the polymer solution. Experi- mental verification of theoretical predictions is part of this research. The kinetics and thermodynamics interaction in miscible polymer blends will also be investigated by the static and dynamic light scattering intensity measurements. By combining the results of mutual and self-diffusion coefficients of the polymer blend, the role of cross velocity correlations between segments of the same chain and between neighboring chains will be clarified. The mutual diffusion coefficient will be measured by using photon correlation spectroscopy, the self diffusion coefficient by pulsed field gradient NM or by the holographic grating relaxation tech- nique whenever appropriate. Understanding of the thermodynamic interactions and the dynamics of local segmental motion is vital to various application of polymers in diverse areas, such as coatings, electronics, optics, and structural materials.

这项对聚合物中局部链段运动动力学的研究将包括半稀释和浓缩区域以及可混溶聚合物共混物中的聚合物溶液。 所使用的技术是各种类型的动态光散射，包括光子相关光谱、布里渊散射和全息光栅弛豫。 将研究半稀释或/和浓缩聚合物溶液中标记链的动态纵向和剪切柔量、动态纵向和剪切模量、高超声速和衰减系数、相互和示踪扩散系数等特性。 光谱将作为聚合物分子量、浓度、散射波矢量和溶剂质量的函数进行测量。 将努力将动态光散射与聚合物溶液的机械弛豫光谱联系起来。 理论预测的实验验证是本研究的一部分。 还将通过静态和动态光散射强度测量来研究可混溶聚合物共混物中的动力学和热力学相互作用。 通过结合聚合物共混物的相互扩散系数和自扩散系数的结果，将阐明同一链的片段之间以及相邻链之间的交叉速度相关性的作用。 互扩散系数将通过使用光子相关光谱来测量，自扩散系数将通过脉冲场梯度NM或在适当的情况下通过全息光栅弛豫技术来测量。 了解热力学相互作用和局部节段运动的动力学对于聚合物在不同领域（例如涂料、电子、光学和结构材料）的各种应用至关重要。