SBIR Phase I: Liquid Crystalline Thermoset (LCT) Adhesives for High-Temperature Applications

*96-60674霍伊特这个小型企业创新研究第一阶段项目旨在开发适合航空航天行业应用的具有热性能和机械性能的粘合剂。对这些材料的理想要求相当严格。材料必须表现出高强度和高断裂韧性，良好的耐化学性和在150℃-370℃范围内的长期热稳定性。虽然在高温胶粘剂方面有大量的研究工作，但目前可用的材料远远达不到理想的要求。我们建议研究液晶热熔体(LCT)系统作为粘合剂应用于高温、高性能环境。与它们的液晶聚合物(LOP)类似物一样，LCT有望在热性能和机械性能以及耐化学腐蚀性方面比它们的非液晶同类产品有显著的提高。此外，液晶材料固有的低熔体粘度应该会在粘合剂应用中带来几个加工优势。所研究的材料将通常以熔体可加工或热致性LCT的已知例子为模型。反应性端基将根据行业标准进行选择；一些专有端基将进行测试。第一阶段的主要产品是第二阶段的系统优化和扩展粘结测试所需的数据。这些数据还应提供有关LCT和粘合剂的结构-性能关系的信息。如果这项工作取得成功，将实现一种新型的高温应用胶粘剂。虽然这些材料的应用最初集中在航空航天工业，但也有潜力用于其他领域，如桥梁和高速运输系统的轻质结构材料。*？？

*** 96-60674 Hoyt This Small Business Innovation Research Phase I project aims to develop adhesives with thermal and mechanical properties suitable for applications in the aerospace industry. The ideal requirements for these materials are rather stringent. The materials must exhibit high strength and high fracture toughness, good chemical resistance and long-term thermal stability somewhere in the range 150 C-370 C. While there is a significant research effort in high-temperature adhesives, currently available materials fall well short of the ideal requirements. We propose to investigate liquid crystalline thermoses (LCT) systems to be applied as adhesives suitable for use in high-temperature, high-performance environments. LCTs, like their liquid crystalline polymer (LOP) analogues, are expected to offer significant enhancements in thermal and mechanical properties and chemical resistance over their non-liquid crystalline counterparts. In addition, the inherent low melt viscosity of liquid crystalline materials should bring about several processing advantages in adhesive applications. The materials investigated will be generally modeled on known examples of melt-processable or thermotropic LCTs. Reactive endgroups will be chosen based on standards in the industry; some proprietary endgroups will be tested. The major product of Phase I is the data required for system optimization and extended bond testing in Phase II. These data should also provide information on structure-property relationships in LCTs and for adhesives in general. If this work is successful, a new type of adhesive for high-temperature applications should be realized. While the application of these materials is initially focused on the aerospace industry, there is potential for use in other areas such as lightweight structural materials for bridges and in high speed transportation systems. *** ??