Sarah Key

University of Leicester


Degradation of plastics: the chemistry and solutions


Dr Shengfu Yang

PhD Summary

By 2015, humans had generated 8.3 billion metric tons of plastics, 6.3 billion tons of which had already become waste. Of that waste total, only 9 percent was recycled, 12 percent was incinerated, and 79 percent accumulated in landfills or the natural environment. Most plastic is non-biodegradable and will remain in the environment for hundreds, or thousands of years. There is an urgent need, therefore, to understand how the plastics degrades and what the major degradation products are. My project studies the degradation of plastics to produce free radicals, which can be detected using cavity ring-down spectroscopy (CRDS), which is highly sensitive and can detect free radicals ejected from plastics when illuminated by UV light. A sunlight simulator is employed as the source of radiation, with two initial experiments performed firstly on typical packaging plastics under vacuum to understand the underlying chemistry, and secondly in the presence of atmospheric molecules such as N2, O2 and H2O to understand their contribution to air pollution and environmental hazards.

What inspires you?

I have always loved animals and nature, and over the past few years I have developed a strong interest in many environmental issues such as climate change and pollution. I think my appreciation of the natural world has stemmed from growing up in a relatively rural area and being around all sorts of animals from a young age.

Previous Activity

As an undergraduate I studied MChem Chemistry at the University of Leeds, with an industrial placement year at Lubrizol Ltd. Here I developed my strong interest in research, as I undertook several research projects in the areas of fuel additive stability and diesel soot characterisation. I then went on to do an N-SERP summer research placement at the University of Nottingham, during which I further studied the characterisation of diesel soot nanoparticles. For my Master’s project I worked as part of the EU H2020 HISENTS programme and studied the interaction of gold and silver nanoparticles with a model biomembrane. The aim was to develop a system that could detect water pollutants and predict the potential toxicity of these materials.

Why did you choose Docotoral Research?

I thoroughly enjoyed my experience of research in an industrial environment at Lubrizol, but found the freedom of academic research during my N-SERP placement and Master’s project really exciting. I love being able to fully throw myself into a project, so studying for a PhD was the natural next step towards a career in research. I chose this project for the opportunity to combine my background in physical Chemistry and my personal interest in the environment.

Why did you choose a CENTA Studentship?

I was particularly interested in a CENTA studentship due to the amazing training opportunities and resources available to students. I also liked the interdisciplinary nature of CENTA, and I feel that the chance to interact with and gain the perspective of students outside of my field will add a new dimension to my project that I may not have otherwise had.

What are your future plans

The skills that I will gain through studying for a PhD with CENTA and the University of Leicester will be invaluable to my career as a researcher. I also feel that being exposed to other areas of environmental research will open my eyes to new topics that may interest me, which may shape my future career. I am unsure of whether I want to go into industry or stay in academia, but I am sure the skills and knowledge developed through my PhD will be essential for either path.