Evidence of plasma-driven decomposition of common plastics exposed to an atmospheric nonthermal discharge

Abstract

A nonthermal, pulsed spark discharge is applied to three polymer powders in Ar and Ar– (Formula presented.) gas mixtures. Hydrogen is introduced to assess plasma-driven decomposition. Gaseous decomposition products, including methane, acetylene, and ethylene, are observed with Fourier-transform infrared (FTIR). Surface modifications are observed on the residual polymer via attenuated total internal reflection-FTIR. Time-averaged rotational, vibrational, and excitation temperatures are characterized in the discharge. The plasma density is found to be around (Formula presented.), with rotational and vibrational temperatures ranging from 1500 to 2200 K and an excitation temperature of 1–2 eV. While spark properties did not change with either gas composition or polymer composition, it was determined that the addition of hydrogen promoted higher concentrations of gaseous phase products (promoting hydrogenolysis).