Thermogravimetric analysis (TGA) was used to investigate thermal and catalytic pyrolysis of waste plastics such as prescription bottles (polypropylene/PP), high density polyethylene, landfill liners (polyethylene/PE), packing materials (polystyrene/PS), and foams (polyurethane/PU) into crude plastic oils. In the first phase of this investigation, a statistical design experiments approach identified reaction temperature and time as the most important factors influencing product oil yield. Kinetic parameters including activation energy determined for both catalytic and noncatalytic processes showed a reduction in activation energy for the catalytic reactions. In the second phase, the interactions of reaction temperature and time with a number of catalysts were investigated to determine the effect on the yield of crude plastic oil. It was found that Y-zeolites increased conversion at reduced temperature for PP and PE while spent fluid catalytic cracking and sulfated zirconia catalysts supported pyrolytic dec...