Advancement of FDM 3D Printable Materials Through Epoxy and Benzoxazine Chemistry

Abstract

The field of additive manufacturing (AM) continues to capture significant interest from both academic and industrial sectors. In order to expand its usage across a broader range of applications, there exists a persistent desire to develop novel materials that are compatible with diverse AM technologies. This dissertation offers a comprehensive exploration of thermoset 3D printing, with the goal of expanding the material options available and enhancing the potential of Fused Deposition Modeling (FDM). The first chapter provides a thorough review of recent advancements in thermoset 3D printing technologies, analyzing material formulations, printing processes, and post-curing methodologies. The second chapter addresses the limitations of FDM due to the restricted availability of commercial materials with reactive functionalities and introduces a new di-telechelic epoxy polymer thermoplastic filament. This filament demonstrates excellent printability in FDM, offering a promising avenue to diversify material options for various applications. Moreover, the dissertation investigates the challenge of associating FDM 3D printing with thermosets, a relatively underexplored area. In Chapter 3, an epoxy-polybenzoxazine-based composite filament is introduced, formulated using the di-telechelic epoxy polymer from Chapter 2, and a benzoxazine monomer to print thermosets. The low-temperature filament extrusion and successful printing, followed by high-temperature post-curing, resulted in an epoxy-polybenzoxazine thermoset with almost 100% thermoset content and excellent thermal properties. Furthermore, the dissertation delves into the synthesis and characterization of main chain benzoxazine polymers incorporating Diels-Alder moieties (DA-MCBPs) in Chapter 4, to be used in FDM 3D printing low shrinkage thermosets. This includes the successful synthesis of monomeric precursors, including furan-functionalized benzoxazine precursors (BA-FBz and BS-FBz) and Bismaleimides (BMIs), followed by DA-MCBP polymer synthesis. The thermal characterization of DA-MCBPs provides valuable insights into selecting suitable DA-MCBPs for further studies and post-curing parameters for FDM 3D printing. This research establishes a foundation for employing DA-MCBPs in unconventional FDM 3D printing, opening avenues for producing thermosets with enhanced thermal properties. Finally, Chapter 5 provides an overview of potential future work for the projects discussed in Chapters 2, 3, and 4.