Triggering Chemical Degradation of Plastics at End of Life Using Light and Environmentally-Neutral Nanoparticles

North Carolina State University, Raleigh NC

Investigators

Abstract

This research focuses on developing strategies to controllably break chemical bonds within polymeric material by adding an inexpensive particle and generating internal heat with applied light. Potential benefits of this research include the development of materials with an additional functionality -- the ability to degrade upon command. Thus this knowledge could enable plastics that are strong and robust during use and then can be triggered to quickly and efficiency break down when the item is no longer needed. This concept follows green design principles by enabling a robust object which can be utilized as many times as possible (without breaking down) and then intentionally transformed into a benign product at the end of life. This strategy would work cooperatively with chemical degradation and provide suitably degraded material for bacterial remediation of plastic. This research tests the hypothesis that the strongly inhomogeneous temperature gradients created in the interior of polymers upon photothermal heating of embedded nanoparticles can be utilized to efficiently trigger thermally-induced bond breaking, possible internal fragmentation of the material, and strongly enhanced degradation as a consequence. Metal nanoparticles strongly absorb light and generate heat as a result. Particles will be incorporated within commercial thermoplastics and biodegradable polymers. The degradation efficacy of photothermal protocols will be compare with that from conventional heating. Aluminum nanoparticles are targeted because they are inexpensive and provide additional thermal energy due to their reaction to aluminum oxide. Aluminum is the most abundant metal on earth and aluminum oxide is an environmentally neutral end product. Enhanced knowledge about the photothermal effect in aluminum nanoparticles, which has previously not been well-explored, will be an additional scientific outcome of this work. Textile Engineering senior design teams will be funded to explore auxiliary topics, such as bacterial remediation, that will enhance the research objectives of this work and contribute to the education of these future engineers and scientists. Senior design students will also develop an interactive experience demonstrating polymer degradation for use in a summer program for high school students, whose demographic historically contains 25% or more STEM unrepresented minorities.