Thermal Degradation Of High Molecular Weight Polyethylene To Obtain Low Molecular Weight Polyethylene Wax

The thermal degradation of high density polyethylene (HDPE) and linear low density polyethylene (LLDPE) to low molecular weight waxes (Mw of ~700) were carried out to study the reaction kinetics of the degradation mechanism under various degradation conditions. The properties of the products produced under the various degradation conditions were also studied to understand the relationship between process and product properties. Thermal degradations were carried over a range of temperatures in two types of reactors, a resin kettle purged with nitrogen in which volatiles were allowed to distill-off, and under pressure in an unvented Parr reactor. These reactors were also operated with and without catalyst to understand the effect that catalyst may have on the degradation kinetics and product. Wax products generated under atmospheric conditions without catalyst had lower polydispersity but took longer to get to the final molecular weight. Catalyzed reactions under atmospheric conditions had higher polydispersity and produced lower molecular weight products that were easily distilled off as volatile liquids and gasses. Pressure reactions with catalyst produced the lowest molecular weight products, however polydispersity was high. Pressure reactions without catalysts produced waxy materials with the lowest polydispersity.