Polymer additives for the enhanced photodegradation of polyethylene Molly I. Parry 1 , Ali Salehi-Reyhani 2 , Gavin Hill 3 , Maxie M. Roessler 1 , George J. P. Britovsek 1 1 Department of Chemistry, Imperial College London, UK, 2 Department of Surgery & Cancer, Imperial College London, UK, 3 Polymateria Ltd, London, UK Whilst plastics have properties them attractive to countless applications, they are limited by their poor degradability and subsequent environmental persistence. 1 One process that can accelerate the breakdown of plastics is photodegradation. This takes place due to carbonyl impurities, which are target sites for radical forming Norrish reactions. The intentional inclusion of these groups within PE analogues gives long chain molecules that degrade upon irradiation. 2 Use of these molecules as additives within PE enhance photodegradability without compromising the properties. 3 Here we discuss routes to potential PE additives that have been synthesised through ring-opening metathesis polymerisation. By exploring the polymerisation of cyclooctene, carbonyl-containing analogues of PE can be accessed. 4 Of particular interest are diblock copolymers consisting of a region containing diketone groups, and a subsequent region analogous to HDPE. 5 Additionally, the increased solubility of poly(cyclooctene) compared to PE chains of similar lengths opens the pathway of downstream oxidation, whilst yielding HDPE upon hydrogenation. To further understand the mechanisms behind PE photodegradation, EPR spectroscopy can be used to study radical pathways. Model compounds can be used represent oxidised PE. Here, the use of spin trapping agents for the detection of short-lived photogenerated radicals in model compounds are discussed.
References 1. R. Geyer, J. R. Jambeck and K. L. Law, Sci. Adv., 2017, 3 , e1700782. 2. A. Ammala, S. Bateman, K. Dean, E. Petinakis, P. Sangwan, S. Wong, Q. Yuan, L. Yu, C. Patrick and K. H. Leong, Prog. Polym. Sci., 2011, 36 , 1015–1049 3. R. von Goetze, A. Aljaber, K. Y. Lee, G. Hill, C. Wallis and G. J. P. Britovsek, Polym. Chem. , 2022, 13 , 6377–6385. 4. O. A. Scherman, R. Walker and R. H. Grubbs, Macromolecules , 2005, 38 , 9009–9014. 5. L. M. Pitet, J. Zhang and M. A. Hillmyer, Dalt. Trans. , 2013, 42 , 9079–9088.
P44
© The Author(s), 2023
Made with FlippingBook Learn more on our blog