Thermolysis, coupled with reactive distillation, was investigated as a process to convert waste olefin-based polymers into value-added products. The degradation of two types of polyethylene, linear low and high density, was investigated. The initial molecular structure of the polymer was found to have a large effect on the rate of molecular weight reduction. The linear low-density polyethylene started to produce volatile products earlier and at a faster rate than the high-density polyethylene. Preferential scission of the side branches from the linear low-density polymer backbone was shown to be one of the first steps of the degradation mechanism. Once the branches were stripped from the linear low-density polyethylene, the degradation products were similar to those produced from high-density polyethylene.