Plastics play an important role in today’s society, but their mismanagement as a waste stream has resulted in an environmental crisis. There is an urgent need to improve chemical recycling technologies that can complement standard mechanical recycling and enable full circularity in the plastics industry. Chemical recycling via pyrolysis is extremely promising for handling polyolefin waste streams. Polyolefins constitute a large percentage of plastic waste given their prevalence in packaging and finding methods to recycle them is key to solving the plastic waste crisis. There is a lack of knowledge on the underlying decay mechanisms occurring when polyolefins are pyrolyzed. This hinders the prediction of products produced from a range of operating conditions and limits the ability of models to determine the feasibility of operating conditions on an industrial scale. The proposed research will develop cutting edge experimentally validated kinetic Monte Carlo models to overcome this gap in knowledge. This information will be leveraged to develop a sophisticated model capable of predicting product distributions under a wide range of operating conditions which is critical for process design and optimization. This model will be of great value to companies when designing profitable plastic pyrolysis plants.