The Impact of Biodegradable Plastics in the Properties of Recycled Polyethylene Terephthalate

Since biodegradable materials are unwittingly mixed with synthetic materials, this work aimed to study the feasibility of reliably identifying some biopolymers, treated as contaminants, in the recycling process of polyethylene terephthalate (PET). The results showed that the miscibility between PET-PLA and PET-PHB is good. However, PHB is degraded in the recycling of PET due to the high processing temperatures used; meanwhile, PET and TPS are poorly miscible, characteristics also reflected in the microstructure. The contaminants decrease the mechanical properties of the recycled PET. WCA, FTIR, and DSC, do not allow to identify of these contaminants. FESEM resulted in the most successful technique to detect the biodegradable polymers in the PET matrix. No significant degradation of PET under composting conditions was obtained due to the presence of biodegradable polymers, and the effects of the biodegradable contaminants continue to reduce the mechanical performance of the recycled PET after 1 year of storage.