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Research into biodegradable polymers helps fight plastic pollution

02 September 2024 | Story André Damons | Photo Supplied

Dr Puseletso Mofokeng — Dr Julia Puseletso Mofokeng, from the UFS’s Department of Chemistry, is doing research into biodegradable polymers for application in disposable product packaging.

A researcher from the University of the Free State (UFS) is contributing to the fight against plastic pollution through her research into biodegradable polymers – large, chain-like molecules – as a more environmentally friendly alternative to petroleum-based plastics.

Plastic pollution is a global environmental problem, with 19 to 23 million tonnes of plastic waste leaked into aquatic ecosystems every year.

Dr Julia Puseletso Mofokeng, Senior Lecturer and Researcher in the UFS Department of Chemistry, hopes her research into how biodegradable polymers can be used in disposable product packaging can influence the industry and policymakers to enforce the use of biopolymers or biodegradable polymers in disposable products. This would help reduce plastic waste and boost environment-conservation efforts.

The United Nations Environment Programme (UNEP) describes plastic waste as a serious environmental problem – humans produce about 400 million tonnes of plastic waste every year. Approximately 36% of all plastics produced are used in packaging, including single-use plastic products for food and beverage containers, approximately 85% of which ends up in landfills or as unregulated waste.

Researching biodegradable polymers

Dr Mofokeng’s desire to solve the waste problem in her community of Bophelong village in Qwaqwa, Free State – where community members dumped and burned all sorts of waste, including plastics – inspired her towards her field of research.

Today, her research is aimed at managing plastic waste to combat environmental and atmospheric pollution (from incineration), conserve energy, and improve water quality, including ensuring safe drinking water.

High levels of plastic waste have led to increased research into and development of biodegradable polymers as an alternative to non-biodegradable materials for short-shelf-life goods (such as packaging for fresh fruit and vegetables).

Biopolymers or biodegradable polymers, explains Dr Mofokeng, are derived from renewable resources including, but not limited to, vegetable oils, starches and animal fats. They can therefore be easily disposed of after use without harming the environment.

“My research is based on the preparation and characterisation of completely biodegradable polymers, their blends, and composites or nanocomposites filled with unmodified or modified inorganic fillers, natural fibres, as well as synthesised carbonaceous materials,” she says.

Such materials are developed for various applications, including packaging, electromagnetic interference shielding (blocking unwanted signals), and the removal of heavy metals and other contaminants from water bodies.

“To achieve these aims, I and my small research group are preparing completely biodegradable polymer blends.”

This involves adjusting their morphology (structure) and some of their properties (thermal, thermomechanical, mechanical, and flame retardancy) to match those of petroleum-based polymers in their replacement for disposable products; by reinforcing with natural fibres, and minerals.

Biodegradable polymers can degrade within a few days to a few years depending on their source, type, and biodegradation method used, while petroleum-based polymers can exist for hundreds to thousands of years without degrading. Moreover, because biodegradable polymers are produced from natural resources, their biodegradation mainly produces carbon dioxide, water, and other non-toxic byproducts, Dr Mofokeng adds.

“Biodegradable polymers can degrade by themselves under natural environmental conditions – in one to three years – or may require human intervention to degrade where composts are prepared or conditions are controlled in order to degrade the polymers. The latter two being the fastest, where it could take days to months. In my previous research project [we] kept polylactic acid filled with short sisal fibre in plain water at 80℃, and all the tested samples degraded within 10 days.”

She and a PhD student are conducting an ongoing experiment involving three different biodegradable polymer systems exposed to different conditions outside and under soil, measuring the rate of biodegradation by mimicking the environmental conditions found in dumping sites and landfills.

Signs of biodegradation on the samples showed clearly after 14 months, with cracks, surface erosion, and a decrease in the initial weighed mass, suggesting that the polymers could be completely degraded within two to three years.

Closer to goal

Dr Mofokeng, who has been a National Research Foundation (NRF) Y2-rated researcher since 2021, says since most food outlets and restaurants in South Africa have already started using paper- and bio-based polymer materials in cutlery, straws, and takeaway packaging, the country seems to be closer to its goal of using biodegradable polymers for disposable packaging.

The UFS, too, is aiming to phase out the use of plastic bottles in the next three to five years. This will be done by installing filtered water machines in all its buildings.

“We are now left with policymakers to enforce strict laws governing production; and retail industries to use biopolymers or biodegradable polymers in disposable packaging materials,” she says.

New research

Dr Mofokeng and her group’s research is in line with the United Nations’ Sustainable Development Goals (SDGs), including ensuring good health and wellbeing (SDG3), providing clean water and sanitation (SDG6), forging sustainable cities and communities (SDG11), establishing sustainable consumption and production patterns (SDG12), and protecting life below water (SDG14).

She has been researching polymers for almost two decades, and remains passionate about her research field and educating communities. Her new research project, in collaboration with colleagues from her department, targets the removal of heavy metals and other contaminants from groundwater. Testing and water treatment is set to take place in different regions in Qwaqwa, specifically among households that collect drinking and cooking water from boreholes.

Dr Mofokeng’s research group was established in 2016 with one honours and two master’s students. She has since supervised nine honours, seven master’s and one PhD student.

She also recently established international research collaborations with the Libyan Advanced Center for Chemical Analysis and the Faculty of Technology at the University of Banja Luka in Serbia.

News Archive

CR Swart Memorial Lecture: Mr Cecil le Fleur

2006-08-08

Khoe and San call for government to speed up policy dialogue with indigenous communities

Mr Cecil le Fleur, leader of the National Khoe-San Consultative Conference and member of the executive management of the National Khoe-San Council, has called for a national policy on indigenous peoples to protect the human rights and special needs of indigenous people in South Africa.

Mr Le Fleur delivered the 38th CR Swart Memorial Lecture on the Khoe and San at the University of the Free State (UFS). He commended the UFS for its serious approach to the Khoe and San and for initiating initiatives such as a research project on the Griqua in which various aspects linked to language, -culture, -history, - leadership, their role in the South African community (past and present) and the conservation of their historical cultural heritages will be covered.

“The policy dialogue with indigenous communities initiated by government in 1999 and supported by the International Labour Organisation (ILO), has been exceedingly slow, owing to political and bureaucratic problems,” said Mr Le Fleur.

According to Mr Le Fleur the slow pace is also impacting negatively on the United Nations’ efforts to expand the international standards and mechanisms for human rights so as to include the special needs of indigenous peoples.

“The successful adoption of a South African policy would probably have a major impact on the human rights culture of Africa and, more specifically, on the UN system,” he said.

“South Africa has a powerful moral authority internationally and is willing to use this authority in multilateral forums. At this stage, however, South Africa’s Department of Foreign Affairs (DFA) may not take an official position on UN instruments and declarations pertaining to indigenous issues, until the Cabinet has resolved its own domestic policy position,” he said.

According to Mr le Fleur it therefore came as a great surprise when the DFA brought out a positive vote in the UN for the adoption of the "Draft Declaration on the Rights of indigenous Peoples" in June this year, even before the completion of the policy process.

Policy consolidation in South Africa is the primary key to creating a new policy climate in Africa in order to protect the rights of indigenous peoples. “The existing constitution of the Republic of South Africa is one of the most liberal on the continent, and embraces the concept of redress of past discrimination. It already includes a clause (Section 6) making provision for the protection of language rights for Khoe and San peoples - the fist peoples of southern Africa,” he said.

“If South Africa can effectively integrate this ‘third generation’ of collective rights within an existing democratic constitution, this will send a clear message to Africa and the world that indigenous rights are a necessary component of human and civil rights in modern democracies,” he said.

Mr Le Fleur proposed an institutional framework based on set principles that would satisfy the needs and aspirations of the Griqua and other first indigenous peoples in South Africa. “The proposed framework was based on the notion of vulnerability as a result of colonialism and apartheid, which stripped us of our indigenous identity, cultural identity and pride as people. This injustice can hardly be addressed within the existing mechanisms provided by the current text of the Constitution,” he said.

Mr Le Fleur also proposed that the principles of unique first-nation status, as recognised in international law, should be applied in the construction of the framework of the constitutional accommodation for the Khoe and San.

Mr Le Fleur further proposed that the Khoe and San’s indigenous status in constitutional terms must be separate from the constitutional acknowledgement of their status as a cultural community, as envisaged in sections 185 and 186 of the Constitution of 1996.

According to Mr Le Fleur, the suggested mechanism should make provision for structures such as:

A statutory representative council for First Indigenous Peoples of South Africa at a national level;
a separate Joint Standing Committee on Indigenous and Traditional Affairs, in both the National Assembly and the National Council of Provinces on which the Khoe and San can be represented;
a representative structure for the Khoe and San in the legislature of each relevant province; and
ex officio membership in the relevant structures of local government.

Media release
Issued by: Lacea Loader
Media Representative
Tel: (051) 401-2584
Cell: 083 645 2454
E-mail: loaderl.stg@mail.uovs.ac.za
24 August 2006

- Full lecture
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