Synthesis and Diffusion Behavior of Thermotropic Poly(ether-amides)

为了研究液晶(LC)聚合物熔体中的扩散行为，我们将制备一类新型的热致性主链聚醚酰胺(简称：S)作为模型聚合物。目标聚合物将通过熔融聚合和多肽合成方法制备，其分子量足够高，在各向同性状态下形成缠绕熔体。将对这些聚合物的中间相性质进行评估。前向反冲光谱(FRES)将被用来确定这些互扩散LC聚合物链的浓度分布。将对液晶聚合物链在近晶、向列相和各向同性相中的示踪和自扩散进行研究。此外，还将探讨在磁场或电场中极化引起的链取向程度对液晶聚合物扩散特性的影响。计划开展合作，利用流变学测量进一步表征这些热致聚合物。这项研究是几个实验室正在进行的了解LC聚合物行为的努力的一部分，LC聚合物越来越多地被用作结构材料。

A new class of thermotropic, main-chain poly(ether-amide)s will be prepared in both deuterated and nondeuterated forms as model polymers for the investigation of diffusion behavior in liquid- crystalline (LC) polymer melts. The target polymers will be prepared by melt polymerization and peptide synthesis methods with sufficiently high molecular weights to form entangled melts in the isotropic state. The mesophase properties of these polymers will be evaluated. Forward recoil spectrometry (FRES) will be used to determine the concentration profiles of these interdiffusing LC polymer chains. Both tracer and self-diffusion studies of LC polymer chains in their smectic, nematic, and isotropic phases will be undertaken. The effect of the degree of chain orientation induced by poling in either magnetic or electric fields will also be explored for its effect on the LC polymer diffusion characteristics. Collaborations are planned which will further characterize these thermotropic polymers using rheological measurements. This research is part of an ongoing effort in several laboratories to understand the behavior of LC polymer, which have increasing use as structural materials.