D.E. Clouse, S.S. Dasari, S.M. Cotton, L.E. Arrambide, S.S. Deshpande, S.A. Hawkins, A.P. Maffe, M.J. Green
Texas A&M University,
United States
Keywords: radio frequency, vitrimer, composite, carbon nanotubes
Summary:
This work demonstrates the radio frequency (RF) heating of vitrimer/epoxy blends incorporated with carbon nanotube (CNT) susceptors. Vitrimers are a growing class of advanced materials that combine the rigidity and strength of thermoset polymers while having the workability of thermoplastics thanks to their ability to undergo dynamic covalent bond exchanges in the presence of elevated temperatures (T > Tv). This work is the first report of a vitrimer/epoxy blend, which exhibits a unique combination of properties, offering enhanced strength compared to traditional vitrimers, while retaining dynamic bond exchange. We show that as the vitrimer content of the blends increased, the ability of the material to exhibit dynamic bond exchange increased. Meanwhile, the glass transition temperature of the blends improved as the epoxy content increased. The addition of CNTs enables an RF heating response, thanks to the nanomaterial’s high electrical conductivity. Using RF to heat vitrimer/epoxy/CNT composites above Tv allows composite samples to be welded together faster than traditional methods. The mechanical properties of the RF-welded composite interface were the same as traditionally welded samples. This work also demonstrates the feasibility of using an automated RF heating process with a hands-free setup to selectively trigger shape memory behavior (T < Tv) and permanent reshaping (T > Tv) in specific areas of the vitrimer/epoxy/CNT composites. This approach holds significant promise for the development of advanced polymer materials with tailored properties and moldable structures for applications in industries such as aerospace, automotive, and construction.