Recycled PET and the Solutions Towards Its Reusability

This chapter delves into the impact of recycling on polyethylene terephthalate (PET), shedding light on the recovery and processing of recycled PET (rPET) with a focus on its rheological, thermal, and mechanical properties. A thorough review of existing literature on chain extension, blending, and vitrimerization is presented, with a specific focus on comparing virgin and recycled PET. The chapter also incorporates recent works by the authors, providing a comprehensive overview of the current state-of-the-art in rPET research. Initially, the chapter examines the effects of recycling on PET, highlighting the molecular weight loss and contaminations observed over multiple recycling cycles. Subsequently, it explores chain extension techniques using pyromellitic dianhydride (PMDA) and Joncryl ADR, which directly address issues related to molecular weight loss and processability. Blending rPET with virgin PET (vPET) is then investigated since it is the most prevalent blending method, which mitigates the impact of contaminants and increases the average molecular weight in a cost-effective way. The discussion progresses to include polybutylene terephthalate (PBT) blends, which address both the recycling-related challenges and inherent drawbacks of PET. Finally, the chapter explores PET vitrimerization, presenting the latest studies in this area as a promising long-term solution for PET recycling, while also expanding its potential for various engineering applications.