Collaborative Research: Thermal and Processing Effects on the Properties of Low Cost Thermotropic Copolyesters

该合作研究项目旨在了解热致液晶聚合物（TLCPs）的加工过程，从而降低目前广泛应用的障碍。这将通过对tlcp的熔体稳定性、流动行为和结构/性质的协调研究来完成。将采用一系列复杂的表征方法来监测熔体在高温下的热稳定性，并采用x射线散射方法来研究与加工相关的简单流动和复杂流动中分子取向（与tlcp的力学性能直接相关）的发展和命运。近年来，这些方法已被有效地应用于纯科学兴趣的“模型”tlcp，但该项目首次提供了使用这些技术对技术相关材料进行全面研究的机会。为了将这些基本信息与产品特性联系起来，通道流斑块将在x射线结果指导下进行成型，并研究其形态和物理特性。这些材料在商业应用中需要优异的加工性，模具填充精度，物理性能，尺寸稳定性和热稳定性。尽管前景可观，但tlcp尚未广泛应用于许多应用中，这些应用可能实现其作为高强度/低重量材料的潜力。影响因素包括加工过程中熔体高温下的热稳定性限制，成型过程中系统的弱方向，以及商用tlcp的高成本。这项工作将以TLCP材料为特色，该材料有可能大幅降低价格（约3美元/磅），从而直接解决成本的核心问题。西北大学和MMI之间的合作为研究生和本科生提供了一个获得最先进表征工具和热分析经验的场所。

This Collaborative Research project is to develop an understanding of the processing of thermotropic liquid crystalline polymers (TLCPs) so that the current barriers to widespread applications are lowered. This will be accomplished through a coordinated study of melt stability, flow behavior, and structure/properties of TLCPs. An array of sophisticated characterization methods will be applied to monitor the thermal stability of the melt at high temperature, and x-ray scattering methods to study the development and fate of molecular orientation (directly related to mechanical properties of TLCPs) in both simple flows and complex flows of relevance to processing. These methods have been productively applied to 'model' TLCPs of purely scientific interest in recent years, but this project affords the first opportunity for a comprehensive study of a technologically relevant material using these techniques. To relate such fundamental information to product properties, channel flow plaques will be molded under protocols guided by the x-ray results, and their morphologies and physical properties studied.These materials are used commercially in applications requiring excellent processibility, mold-filling precision, physical properties, dimensional stability, and thermal stability. Despite considerable promise, TLCPs have yet to be broadly applied in numerous applications where their potential as high strength/low weight materials might be realized. Contributing factors include thermal stability limitations at high temperatures in the melt during processing, systematically weak directions in moldings, and the high cost of commercially available TLCPs. This work will feature a TLCP material that offers potential for dramatic price reductions (approximately $3/lb), thereby directly addressing the central issue of cost. The collaboration between Northwestern University and MMI provides a venue for graduate and undergraduate students to gain experience in state-of-the art characterization tools and thermal analysis.