A new composite material made from invasive Port Jackson trees and recycled low-grade plastic waste could help eradicate South Africa’s social housing crisis.
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The material was developed by Dr Abubakar Sadiq Mohammed, whose research showed that a combination of these two types of waste could be used to build better, low-cost houses.
Dr Mohammed received his PhD in wood product science from Stellenbosch University’s (SU’s) Faculty of AgriSciences in December last year.
His dissertation, titled Properties of wood-plastic composites made from alien invasive tree waste and recycled low-density polyethylene for interior use in social housing, underlines the urgent need to find sustainable solutions for South Africa’s social housing challenges.
Through his research, he was able to develop a wood-plastic composite comprising a mix of biomass from all parts of a Port Jackson tree (Acacia saligna) and recycled, low-density polyethylene.
‘Plastic waste is a known global menace, so the idea was to transform this waste material into something useful,’ Mohammed said.
‘I was also interested in developing affordable, eco-friendly alternatives to existing low-cost building materials.’
Wood-plastic composites are generally made from recycled plastic and small wood particles or fibres.
Manufacturers typically separate the woody parts of the chosen plants from the non-woody parts (such as bark, leaves and seeds). Previously, the non-woody parts of alien invasive trees were considered contaminants rather than suitable components from which to produce composite materials.
However, Mohammed analysed the physical and mechanical properties of the new composite boards and determined the performance of the material in terms of certain processing requirements.
He specifically tested the boards’ resistance to mould infestation and analysed their fire-resistant properties while considering the impact of the thermal degradation of the individual biomass constituents (such as bark, twigs, leaves and wood) on the physical, mechanical, acoustic and thermal insulation properties of these boards.
His research showed that wood-plastic composites made with Port Jackson trees have better mechanical properties, regardless of their exact composition, compared to two other invasive species, black wattle (Acasia mearnsii) and red river gum (Eucalyptus camaldulensis).
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Picture: Supplied