A.D. Saha, P. Choudhury, Y. Lee, J. McCoy, S. Chowdhury
New Mexico Tech,
United States
Keywords: Plasmonic Nanoparticles, Photothermal curing, Epoxy nanocomposites, Nanoscale mechanical properties
Summary:
The incorporation of photothermal nanoparticles in epoxy systems provides us with a promising opportunity to use light-induced heating to cure epoxies. To develop sustainable recyclable epoxy, we incorporated Diels–Alder reactions in epoxy to develop a recyclable thermoset which can be reversibly liquified at higher temperature and solidified upon cooling. We incorporated photothermal nanoparticles such as refractory plasmonic titanium nitride nanoparticles (TiN NPs) into the Diels–Alder (DA) modified epoxy. Refractory plasmonic Titanium Nitride (TiN) nanoparticles, in particular, can absorb light to generate localized heating, drive the polymerization reaction and allow us to utilize renewable energy efficiently. However, due to the localized heating at photothermal nanoparticle surface, there could be temperature gradients in the matrix which is different than the conventional heating. Additionally, light exposure can trigger undesirable side reactions, potentially compromising the final mechanical properties of the material. We found that these side reactions can be minimized under controlled atmospheric conditions such as nitrogen environment. Interestingly, minimizing the side reactions we could see enhanced curing rate for reversible epoxy in comparison to conventional heating at similar bulk temperatures. We are currently studying how the nanomechanical properties of the photothermally cured samples compare with the heat cured samples. This study provides fundamental insights into how we can leverage light for driving epoxy curing in an energy efficient way.