CAREER: Understanding the Process-Structure-Property Relationships in Polymer Nanocomposites Reinforced with Gas-Phase-Synthesized Graphene

该学院早期职业发展（Career）基金支持石墨烯增强纳米复合材料可扩展制造的基础研究。这类纳米复合材料重量轻，强度高，可以实现各种各样的新应用，例如提高燃油效率的更安全的车辆，改善散热的抗冲击电子产品，以及能够产生更多可再生能源的轻质风力涡轮机叶片。然而，目前石墨烯基纳米复合材料的制造工艺使用通过石墨剥离获得的石墨烯。剥落石墨烯增强纳米复合材料表现出三个限制性能增强的基本挑战：缺陷、分散和聚集。此外，生产脱落的石墨烯需要有害的酸和纯净水，并产生有毒的副产品。将气相合成的石墨烯加入聚合物中可以克服这些挑战。本项目旨在探索气相合成石墨烯增强聚合物基纳米复合材料的工艺、结构和性能之间的关系。该研究通过揭示新的强化和热传递机制、加工条件以及石墨烯-聚合物相互作用来促进科学的进步，从而促进了对复合材料的基本理解。这个多学科项目整合了制造业、材料科学和化学领域，并通过将低收入、潜在的第一代大学生纳入哈维马德学院联邦资助的“向上发展计划”，扩大了代表性不足群体的参与。该基金创建并免费传播一门新的纳米复合材料课程，该课程采用了增强学生学习的新技术，从而改善了STEM领域的教育。目前对石墨烯基纳米复合材料的理解主要是基于含有脱落石墨烯的聚合物，因为石墨烯在衬底上的化学气相沉积对于制造纳米复合材料是不切实际的。该项目的具体目标是通过发现气相合成石墨烯（GSG）增强聚合物的加工-结构-性能关系来改变对石墨烯基纳米复合材料的理解。GSGs是通过在大气氩等离子体中分解乙醇而产生的。本研究的目标是通过(1)将石墨烯分散在热固性树脂中，并通过在模具中固化分散体来制造纳米复合材料，(2)使用可扩展的复合工艺将石墨烯与热塑性塑料混合，并通过注塑成型纳米复合材料，(3)通过拉伸测试确定纳米复合材料的强度和刚度，(4)使用瞬态平面源方法测量纳米复合材料的导热性。(5)利用电子显微镜技术将性能增强与纳米复合材料微观结构相关联。该项目产生了新的知识，推动了复合材料、材料科学和化学领域的发展，并使石墨烯基纳米复合材料的环保高通量制造成为可能。它确立了PI在纳米复合材料先进制造领域的长期职业生涯，为交通、可再生能源和环境方面的挑战提供解决方案。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This Faculty Early Career Development (CAREER) grant supports fundamental research on the scalable manufacturing of graphene-reinforced nanocomposites. This class of nanocomposites are lightweight and high strength and they can enable a diverse range of new applications, such as safer vehicles with increased fuel efficiency, impact-resistant electronics with improved heat dissipation, and lightweight wind turbine blades capable of generating larger amounts of renewable energy. However, current manufacturing processes for graphene-based nanocomposites use graphene obtained through the exfoliation of graphite. Nanocomposites reinforced with exfoliated graphene exhibit three fundamental challenges that limit enhancements in properties: defects, dispersion and aggregation. Furthermore, producing exfoliated graphene requires hazardous acids and purified water and generates toxic byproducts. Incorporating gas-phase synthesized graphene into polymers can overcome these challenges. This project aims to discover the relationships between the processing, structure and properties of polymer-matrix nanocomposites reinforced with gas-phase synthesized graphene. The research promotes the progress of science by revealing new strengthening and thermal transport mechanisms, processing conditions, and graphene-polymer interactions that advance the fundamental understanding of composite materials. This multidisciplinary project integrates the fields of manufacturing, materials science, and chemistry, and broadens the participation of underrepresented groups through the inclusion of low income, potential first-generation college students in the federally-funded Upward Bound Program at Harvey Mudd College. The grant creates and freely disseminates a new nanocomposites course that employs novel techniques that enhance student learning, which improves education in STEM fields.The current understanding of graphene-based nanocomposites is largely based on polymers containing exfoliated graphene because the chemical vapor deposition of graphene on substrates is impractical for manufacturing nanocomposites. The specific goal of this project is to transform understanding of graphene-based nanocomposites by discovering the processing-structure-property relationships in polymers reinforced with gas-phase synthesized graphene (GSG). GSGs are produced through the decomposition of ethanol in atmospheric argon plasmas. The goal of this research is achieved by (1) dispersing graphene in thermosetting resins and fabricating nanocomposites by curing the dispersions in molds, (2) mixing graphene with thermoplastics using scalable compounding processes and forming nanocomposites by injection molding, (3) determining the strength and stiffness of nanocomposites through tensile testing, (4) measuring the thermal conductivity of nanocomposites using the transient plane source method, and (5) correlating property enhancements with nanocomposite microstructures using electron microscopy techniques. This project generates new knowledge that advances the fields of composites, materials science, and chemistry, and enables the environmentally friendly high-throughput manufacturing of graphene-based nanocomposites. It establishes the PI’s long-term career in the advanced manufacturing of nanocomposites that provide solutions to challenges in transportation, renewable energy, and the environment.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.