CAREER: Additive Manufacturing of Polymer Composites via in-situ Polymerization

传统的纤维增强聚合物复合材料制造速度慢、能源效率低、劳动密集型。它需要使用昂贵的模具，严重限制了复杂复合结构设计和制造的灵活性。增材制造为快速创建所需的复合材料结构提供了一种有前途的替代方案，而无需模具；然而，高质量纤维增强复合材料的增材制造具有挑战性，主要是因为在沉积之前很难将基体聚合物与固体纤维增强均匀混合，然后沿着所需的打印路径将其固化。该学院早期职业发展（Career）奖将支持基础研究，该研究将通过在打印过程中瞬间固化复合材料，实现含有高浓度碳纤维的复合材料的增材制造。如果成功，该项目将为无模具甚至空中快速制造复合材料奠定理论基础。该项目将提供实践活动，鼓励科罗拉多州的初高中学生，特别是女性和西班牙裔/拉丁裔学生参与STEM教育。将开发新的课程和体验活动来培训下一代复合材料劳动力。目前用于连续纤维增强聚合物复合材料的增材制造方法主要集中在使用热塑性聚合物或光固化树脂作为复合材料的基体聚合物，这些材料通常具有较差的机械性能和/或难以用高体积分数的纤维加工。本项目将研究一种基于原位热聚合复合材料基体树脂的新型复合材料增材制造方法的制造科学。该项目的核心是一个新的复合材料制造平台，该平台使用远程刺激局部加热复合材料长丝的热敏性液体树脂，以立即聚合和固化打印的复合材料。该项目将阐明工艺参数、材料组成和性能的时空变化以及印刷复合材料的多尺度性能之间的内在相互作用。该研究有望揭示相邻层之间界面形成和键合控制的机制。实验和数值研究将用于了解制造过程中沿多层曲线路径的长丝内的粘弹性变形行为和纤维分布。最后，将开发一种新的传感和控制框架，用于在制造过程中确定材料的多尺度物理和热化学性质，并动态更新加工参数，以制造高质量的复杂复合材料结构。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。

Traditional manufacturing of fiber-reinforced polymer composites is slow, energy-inefficient, and labor-intensive. It requires using expensive molds that severely limit the flexibility in the design and fabrication of complex composite structures. Additive manufacturing provides a promising alternative for rapidly creating desired composite structures without needing molds; however, additive manufacturing of high-quality fiber-reinforced composites is challenging, mainly because it is difficult to mix the matrix polymer with solid fiber reinforcements uniformly prior to deposition and then rigidize them in place along the desired print path. This Faculty Early Career Development (CAREER) award will support fundamental research that will enable additive manufacturing of composites containing a high concentration of carbon fibers by instantaneously rigidizing the composite material during the printing process. If successful, this project will lay a theoretical foundation for rapid manufacturing of composites without molds or even in midair. This project will provide hands-on activities to encourage Colorado’s middle and high school students, particularly women and Hispanic/Latinx students, in STEM education. New courses and experiential activities will be developed to train the next generation of composites workforce.Current approaches for the additive manufacturing of continuous fiber-reinforced polymer composites are mainly focused on using thermoplastic polymers or photocurable resins as the matrix polymer of composites, which typically have poor mechanical properties and/or are hard to process with a high volume-fraction of fibers. This project will investigate the manufacturing science of a new composite additive manufacturing method based on in-situ thermal polymerization of the matrix resin of composites. Central to this project is a new composite manufacturing platform that uses a remote stimulus to locally heat the thermo-responsive liquid resin of the composite filament to instantaneously polymerize and rigidize the printed composite. This project will elucidate the intrinsic interplay between process parameters, spatiotemporal variations in material composition and properties, and multiscale performance of printed composites. The proposed research is expected to uncover the mechanisms of interface formation and bonding control between adjacent layers. Experimental and numerical studies will be used to understand the viscoelastic deformation behavior and fiber distribution within filaments along multilayered, curvilinear paths during the manufacturing process. Finally, a new sensing and control framework will be developed to determine multiscale physical and thermochemical properties of materials during the manufacturing process and update the processing parameters on the fly to manufacture high-quality complex composite structures.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.