Page 33 - Thetha Issue 7

WATCH THIS SPACE: PHD RESEARCH

Director of the University’s Centre for
Rubber Science and Technology, as
well as Stellenbosch University’s chief
researcher in renewable polymers,
fuel and rubber chemistry, Professor
Christopher Woolard.
It involved three years of
research, testing, comparing
and re-testing, and included
looking at varying amounts
of wild garlic extract as
well as parameters of the
sophisticated technology
employed, including
temperature, pressure,
and time. Three scientific
Dr Jabulani Mnyango
papers on the Tulbaghia
Garlic Boost for violacea Har. plant usage for
eco-friendly
devulcanisation
have been published in high-
Old Tyres impact peer-reviewed journals.
“I was very pleased with what I
achieved using the plant as it is a green or eco-
friendly process, which is wonderful.
ld motor vehicle tyres are a huge waste – and “However, it still requires energy in the form of
recycling – challenge in South Africa, as the electricity to devulcanise. The gain is that the plant process
rubber needs to be softened, or devulcanised, requires far lower temperatures than the common chemical
Obefore it can be re-used. process; thus, lower energy consumption.”
Dr Jabulani Mnyango, who graduated with his PhD in Commercialising the process lies further down the
Chemistry in April 2023, has tackled this in an eco-friendly line. Dr Mnyango hopes to conduct postdoctoral research
way by using the indigenous plant known colloquially as overseas and to advance the study of eco-friendly
wild garlic. approaches for recycling rubber and plastic. He aspires to
“The problem is that the current methods used for achieve the latter by working
devulcanisation include chemical agents that are expensive in both academia
and toxic to the environment,” notes Dr Mnyango. and industry.
His PhD research focused on the plant, Tulbaghia
violacea Harv., as a readily available and non-toxic agent
that could contribute to softening rubber.
His findings showed that crude extracts of the plant can
significantly devulcanise and help to produce high-quality
rubber for re-use. Its impact was similar to that of the
toxic chemical agents other researchers had worked
with, which suggests Dr Mnyango’s devulcanisation
approach has been a huge success.
“My co-supervisor Dr Buyiswa Hlangothi, the
Acting Director of the School of Biomolecular
and Chemical Sciences, was already working
with a number of plants from the Eastern
Cape region,” says Dr Mnyango.
“Her research interest is medicinal plant
chemistry and she put me onto Tulbaghia
violacea Harv. specifically, because of its
sulphur compounds, which are required
for devulcanisation.”
So began his PhD, co-supervised
by Dr Buyiswa Hlangothi, and
Professor Percy Hlangothi, who is

2023 | mandela.ac.za | 31