1. Department of Chemical Sciences, University of Johannesburg, Doornfontein Campus, Johannesburg 2028, South Africa
2. Department of Chemistry, Center for Rubber Science and Technology, Nelson Mandela University, Gqeberha 6031, South Africa
3. Science Advisory and Strategic Partnerships, Academy of Science of South Africa, Pretoria 0040, South Africa
4. Department of Environmental Health, Nelson Mandela University, Port Elizabeth 6031, South Africa