Date of Award

January 2022

Document Type


Degree Name

Master of Science (MS)


Chemical Engineering

First Advisor

Bethany Klemetsrud


Plastic is one of the most widely used packaging materials; however, there are limited processes in place for recycling at the end of its life, especially for plastics 3-7 including: PVC, low-density polyethylene (LDPE), polypropylene (PP), and polystyrene (PS). Pyrolysis, or chemical recycling, has shown to be promising to break plastics down to fuels, monomers, or other chemicals. This has been shown to also make use of mixed plastic. This work studies the interactions during fast pyrolysis between commonly unrecyclable plastics. Chapter II investigates the interaction of PS and PP in fast pyrolysis at temperatures of 450, 500, and 550 °C with mass ratios of PS:PP at 1:8, 1:1, and 8:1 via a full factorial experimental design. Chapter III investigates the interactions of PS and LDPE at the same temperatures and mass ratios. Using relative areas of extracted ions for pyrolytic products, previous findings were confirmed that the addition of polystyrene to polypropylene and polyethylene increases the amount of light gases produced. Unreported interactions of polystyrene and polypropylene affecting the yield of mid-range hydrocarbon products and styrene were observed, likely due to increased composition range compared to previous studies, providing insight to secondary reactions occurring during co-pyrolysis.