Self-healing thermoset polymers and embedded 3D printing VIA chemical activation

Thermoset polymers and composites are crucial in modern aerospace, automotive, marine, and energy industries due to their superior specific stiffness, strength, thermal stability, and chemical resistance. These properties facilitate the creation of the next generation of lightweight, energy-efficient, and multifunctional structures. This dissertation explores enhancements in functionality, such as self-healing properties, alongside advanced manufacturing techniques like 3D printing to enable the precision fabrication of these complex materials. The research includes developing new chemistries and formulations that withstand high temperature processes essential for curing processes, thereby improving the efficiency and capabilities of manufacturing processes to create multifunctional composites. Frontal polymerization (FP) has emerged as a rapid, energy-efficient, and scalable technique for manufacturing bulk polymeric materials, offering significant potential to streamline the production of multifunctional polymers and composites. This research discusses the integration of thermally stable self-healing features into FP resins. The development of thermally stable microcapsules designed to withstand temperatures around 200 °C is crucial for self-healing applications. A thermally latent bis-N-heterocyclic Ru-carbene catalyst, chemically activated by Cu(I) species, enhances thermal stability and preserves the self-healing components throughout the curing process, demonstrating a self-healing efficiency of approximately 91%. In addition, this work showcases embedded 3D printing for fabricating thermoset polymers, overcoming many limitations of traditional 3D printing methods for soft thermosets. The process involves a latent precatalyst ink that is activated within the matrix, using a dual-purpose matrix that provides physical support and facilitates efficient in situ curing. This process forms a solid crust during the initial reaction, maintaining the printed shape regardless of the matrix's properties and subsequently fully curing the resin within the diffusion limit. Through the partial pre-polymerization of dicyclopentadiene (DCPD) and 1,4-cyclooctadiene (COD) to create comonomer inks, 3D-printed copolymers with diverse mechanical and thermochemical properties are fabricated. The methodology described here can create intricate chain and hair-like structures of thermosets and elastomers. These advancements not only enhance the durability and functionality of thermoset materials but also open new avenues for the design and fabrication of advanced materials.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Materials Science & Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2024

Author dc:creator

• Lee, Young Bum

Contributors dc:contributor

• Braun, Paul V
• Evans, Christoper M
• Ewoldt, Randy H
• Sottos, Nancy R

• Chemical Activation
• Self-healing
• 3d Printing

Statement dc:rights

• Copyright 2024 Youngbum Lee

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/127436

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F127436