Naseri, Iman, authorJames, Susan, advisorBailey, Travis, committee memberHerrera-Alonso, Margarita, committee memberMa, Kaka, committee member2024-05-272025-05-202024https://hdl.handle.net/10217/238523Fiber-reinforced polymer composites (FRPCs) are widely used in a variety of applications owing to their excellent specific mechanical properties, chemical stability, and fatigue resistance. However, the state-of-the-art technologies for manufacturing FRPCs are intensive in terms of time and energy, generate a significant carbon footprint, and require costly resources. In addition, FRPCs lack key non-structural functionalities (e.g., de-icing, damage sensing) required for many applications. Despite the enormous efforts made to improve the manufacturability of FRPCs and address the shortcomings associated with the performance of FRPCs, there is still a pressing need for alternative manufacturing technologies to enable the rapid, energy-efficient, and low-cost manufacturing of multifunctional fiber-reinforced polymer composites. In this dissertation, a novel technique for rapid and cost-effective manufacturing of multifunctional fiber-reinforced polymer composites is developed by exploiting the frontal polymerization concept and joule heating of nanostructured materials. A nanostructured paper or fabric is integrated into the composite layup to supply the energy required to trigger frontal polymerization via the Joule heating effect. In addition, the nanostructured paper remains advantageous in in-service conditions and imparts new functionalities to the host composite structure. In the first chapter, the recent developments in material systems, as well as heating techniques reported for improving the manufacturability of FRPCs, are reviewed, and frontal polymerization (FP) as a rapid and energy-efficient technique for curing thermoset matrix composites is introduced. In the second chapter, frontal curing of multifunctional composites via a commercial nanostructured heater (buckypaper) is demonstrated, and the curing behavior of composite laminate is studied under various layup conditions. It is demonstrated that the through-thickness FP manufacturing strategy using an embedded buckypaper surface heater allows for rapid and energy-efficient manufacturing of fully cured composite panels using the conventional tooling materials utilized in the composite industry. However, the temperature profiles developed during the cure cycle, as well as the degree of cure of resin in produced composites, are greatly affected by the thermal properties of the tooling materials, where lower front temperatures and degree of cure are measured for composite panels manufactured using thermally conductive tooling materials such as aluminum. This issue can be effectively addressed by preheating the dry composite layup for a few minutes. Despite the relatively uniform heat generation in nanostructured buckypaper heaters, the infrared thermal imaging of the curing process reveals that the front initiates from multiple locations and propagates in both the through-thickness and in-plane directions. In addition, the de-icing functionality is demonstrated in the cured composite as one of the several possible functionalities imparted to composite structures due to the presence of a buckypaper layer. In the third chapter, a fabric heater is developed by writing laser-induced graphene on aramid fabric using a CO2 laser and used as an integrated heater for manufacturing FRPCs via the through-thickness FP manufacturing technique. A 10 cm × 10 cm composite panel is successfully cured within only 1 minute with a total energy consumption of 4.13 KJ, which is comparable to the time and energy required for producing a similar composite panel using a buckypaper heater. In addition to composite manufacturing, flexible heaters are prepared with the addition of silicone rubber to fabric heaters. Although the addition of electrically insulating rubber negatively affects the electrothermal performance of fabric heaters, it greatly improves the durability of fabric heaters. In the fourth chapter, a facile and rapid technique for the preparation of mechanically robust nanocomposite film heaters is developed based on a frontally polymerizable resin system. The mechanical and electrothermal properties of the nanocomposite film heaters are characterized, and the produced heaters are used for out-of-oven manufacturing composite laminates. In the final chapter, the main research findings are summarized, and the recommendations for future studies are presented.born digitaldoctoral dissertationsengCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.frontal polymerizationrapid manufacturingmultifunctional compositefiber-reinforced polymer compositeTextEmbargo expires: 05/20/2025.