Circular Polyolefins: Advances toward a Sustainable Future
Davood Hassanian-Moghaddam, Narges Asghari, Mostafa Ahmadi
Abstract
Plastics offer several advantages, but their production and disposal processes have severe environmental implications. To overcome these issues, there is a need to switch from the linear to a circular economy by recycling plastic waste and by utilizing renewable resources to create bioplastics. However, this is challenging in the case of nonbiodegradable polyolefins (POs), which form the largest fraction of produced polymers and the least recycled one. Mechanical recycling, chemical recycling, and PO bioplastics are the three pillars of PO circular economy. Although mechanical recycling is an environmentally and economically viable option, it often results in the degradation and downgrading of POs. Nonetheless, innovations in mechanical recycling, such as the use of (nano)fillers or compatibilization with olefin block copolymers, attempt to mitigate these issues. Furthermore, the development of covalent adaptable networks improves the mechanical properties of recycled PO thermoplastics and provides recyclable PO elastomers. If mechanical recycling fails to meet the desired characteristics of the recyclate PO, chemical recycling to other chemicals is a potential alternative. Although retrieving the monomer is ideal for achieving a closed-loop circular economy, traditional approaches for the noncatalytic chemical recycling of POs are energy-intensive and lack specificity. This has been tried to be addressed by advancements in catalytic approaches. Finally, biobased polyolefins, especially those produced through emerging nonbiochemical approaches, offer attractive alternatives that can be integrated into existing petrochemical plants. With this comprehensive perspective on POs circular economy academic and industrial researchers of the field can better contribute to a more sustainable future.