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3D-printing turns waste material into quality products

Researchers at Kenya’s Jomo Kenyatta University of Agriculture and Technology (JKUAT) have developed ways to turn waste materials into quality and novel industrial products using 3D-printing, also known as additive manufacturing (AM).

James Mutua, a lecturer at JKUAT’s mechanical engineering department, who specialises in additive manufacturing and materials processing engineering, has been working with his team since 2019 to find sustainable solutions to energy and environmental problems.

Additive manufacturing or 3D-printing is the process of creating an object by building or ‘printing’ it one layer at a time.

It does this by depositing material in thin layers to precise measurements until the final product is complete. It is a versatile manufacturing process in that it can use a wide range of materials, including plastics, metals, ceramics and composites.

According to Mutua, their research has proven that AM can be used successfully to turn waste material into real-world energy solutions and products. Plastic scraps, coconut husks, sugarcane remains, and other agricultural waste can now be used as building blocks for cutting-edge manufacturing processes.

“Our research involves a process that combines plastic waste with other waste products to create new and quality industry-ready materials,” Mutua said.

“Using the same process, we have also managed to find a way to make plastic biodegradable by combining it with silica, biophenols and other compounds that we extract from coconut husks and other agricultural waste products,” Mutua told University World News.

“The materials that we produce from the plastic waste are not only biodegradable but are also stronger and more durable than what is available on the market,” he said. “Our plastic products, for instance, have a tensile strength of up to 59 megapascals, compared to those in the market which have a strength of about 38 to 40 megapascals.”

Tensile strength is the maximum stress that a material can withstand while being stretched or pulled, before breaking.

Research applications

While most of the team’s products are still in the prototype stage, some have already been rolled out as functioning units, awaiting certification and partner funding for mass production. “Some of the products we have been able to manufacture include wind turbine blades, filaments for 3D-printing, fuel cells, solar panel frames, biofilter materials and orthotic devices,” Mutua said.

“Our fuel cells are also completely made from recycling plastic, and this includes burning the plastic to get carbon black which we turn into conductors through a doping process. This means that our fuel cells are reusable and cheaper compared to the ones available on the market now,” he added.

Mutua explained that, since going to the recycling industries to make their materials was expensive, they had to customise the equipment they had available at the institution to fit their needs. “We had to design, fabricate, and optimise our own equipment locally, such as heat press machines, shredders and plastic extruders.

“This helped us cut down on our manufacturing cost from KSh5 million (about US$38,700) to about KSh500,000,” he explained. The low-cost equipment also makes the process scalable for wider community use.

Environmental impact

According to Mutua, their research has also found a way to help counter other environmental and social problems. Discarded plastic has become a nuisance to society, especially in Africa which is lagging behind in plastic waste management and recycling. Globally, there have been calls for sustainable solutions to control this menace, and their research may just help to solve this problem.

Since their materials rely on recycling plastic waste, it can help reduce the amount of plastic waste. Because their plastic materials are also biodegradable, this limits future plastic pollution.

The use of agricultural waste also means less of a strain on landfills which, in turn, limits the potential spreading of disease and air pollution from greenhouse gases. It could also reduce littering and create jobs, thanks to the increased economic value of waste material, including farmers who could get higher prices for agricultural waste products.