Cold plasma recycling of plastics Mariano Marco Tobias 1 , Humphrey H. P. Yiu 1 , Martin R. S. McCoustra 1 , David G. Bucknall 1 , Ocean Cheung 2 , Ribooga Chang 2 , David J. Scurr 3 , Anna M. Kotowska 3
1 School of Engineering and Physical Sciences, Heriot-Watt University, UK, 2 Department of Materials Science and Engineering, Uppsala University, Sweden, 3 School of Pharmacy, University of Nottingham, UK
Recycling plastic wastes is challenging as global plastic production and consumption has been rapidly increasing in recent years.This challenge has been exacerbated due to the long-time scales required for polymer degradation in the natural environment. 1 According to a Royal Statistical Societyreport in 2018,90.5% ofplastic waste has never been recycled. 2 The aim of this study is to rapidly reduce the time frame for polymer degradation by using cold plasma technology for depolymerisation of waste plastics and to produce value-added chemicals in a simple, scalable fashion with enhanced energy efficiency. Five of the most common types of plastics polyethylene (PE), polystyrene (PS), polyethylene terephthalate (PET), polyvinyl chloride (PVC) and polypropylene (PP) were chosen in this study to observe the plasma-surface interaction and depolymerisation processes. To monitor the surface morphology and functionalisation, analytical techniques such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were employed. When air is used as the plasma gas source, PVC showed the highest degradation rate while PS degraded the slowest. In addition, modifications of the surfaces have also been observed, most notably the introduction of oxygen and nitrogen groups, and in the case of PVC, dechlorination of the surface can also be observed. Overall, we can conclude that PVC, PE, and PP showed similar degradation behaviours while PS and PET degraded in a similar but different manner. References 1. N. Singh, D. Hui, R. Singh, I.P.S. Ahuja, L. Feo, F. Fraternali, Composites Part B: Engineering , 2017, 115 , 409-422 2. Royal Statistical Society, https://rss.org.uk/news-publication/news-publications/press-release/, (accessed September 2020)
P34
© The Author(s), 2023
Made with FlippingBook Learn more on our blog