Advanced Interpenetrating Networks for Structural Applications

结构聚合物和纤维增强聚合物复合材料在民用基础设施、能源、航空航天和汽车工业中的应用日益突出。环氧树脂因其强度和刚度而成为结构应用中的主要材料。然而，环氧树脂也是脆性的，基本上是弹性的，直到破坏，几乎没有能力重新分配应力和能量的耗散。该项目的目标是通过合成和表征传统环氧树脂与多双环戊二烯的新型互穿网络来开发坚韧的环氧树脂，多双环戊二烯是一种众所周知的延展性和坚韧性的商用聚合物。该项目的假设是，互穿网络将结合其两种成分的优势特性，从而与传统结构环氧树脂相比，表现出优越的开裂和脱粘行为。在这些材料的开发过程中获得的知识将提供对控制互穿网络形成的关键参数，材料制备过程中的结构演变以及材料结构与宏观物理性质之间关系的更好理解。随着工程师们越来越适应复合材料在结构应用中的使用，他们正在采用更厚、更大的结构部件来满足更苛刻应用的负载要求。例如，一些现代商用客机采用纤维增强聚合物复合材料；同样，玻璃纤维复合材料通常用于制造风力涡轮机叶片。在民用基础设施中，厚的高模量碳纤维增强聚合物已被研究用于修复和加固老化的钢结构。尽管成本较高，但环氧树脂粘合剂最常用于粘合结构应用的复合材料。该研究项目将开发一种新型材料，既保持环氧树脂的优势特性（高强度和刚度），又具有韧性和抗压裂性。教育项目将与研究目标紧密结合，包括为K-12学生开发一个实践推广项目，并让本科生和研究生参与研究，强调将学生留在工程领域，并教育学生了解聚合物对社会的影响。

The implementation of structural polymers and fiber reinforced polymer composites in civil infrastructure, energy, aerospace, and automotive industries has been steadily gaining prominence. Epoxy resins are dominant materials used in structural applications due to their strength and stiffness. However, epoxy resins are also brittle and essentially elastic up to failure with little capacity for redistribution of stresses and dissipation of energy. The objective of this project is to develop tough epoxy resins through the synthesis and characterization of novel interpenetrating networks of traditional epoxy resins with polydicyclopentadiene, a commercially available polymer that is well-known to be ductile and tough. The hypothesis of this project is that an interpenetrating network will combine the advantageous properties of both of its constituents thereby exhibiting superior cracking and debonding behavior as compared to traditional structural epoxy resins. The knowledge gained in the development of these materials will provide a greater understanding of critical parameters governing interpenetrating network formation, structural evolution during the material preparation, and relationships between the material structure and macroscopic physical properties. As engineers become more comfortable with the use of composites in structural applications, they are adopting thicker and larger structural components to meet the load requirements of more demanding applications. For example, some modern commercial airliners implement fiber reinforced polymer composites; similarly, glass fiber composites are commonly used to fabricate wind turbine blades. In civil infrastructure, thick, high modulus carbon fiber reinforced polymers have been investigated to repair and strengthen deteriorated steel structures. Despite their higher costs, epoxy resin adhesives are most commonly used to bond composite materials for structural applications. This research project will result in development of a new class of materials that maintain the advantageous properties of epoxy resins (high strength and stiffness), yet are also tough and resistant to fracturing. Educational programs will be closely integrated into the research objectives, including the development of a hands-on outreach program for K-12 students and participation of undergraduate and graduate students in the research, emphasizing retaining students in engineering and educating students on the impact of polymers on society.