A New Life for Waste Plastics and Coffee Grounds


Coffee grounds used to develop biocomposites a step towards environmental sustainability.

Dr. Manjusri Misra and Dr. Amar Mohanty set out to produce biocarbon from used coffee grounds. They then tried to use this biocarbon, along with a blend of recycled PET and LLDPE, to develop sustainable biocomposites. The team collected spent coffee grounds from the U of G campus and used pyrolysis to convert them to biocarbon.

Next, the team made plastic pellets from water bottles from a grocery store. They mixed the pellets as well as bale wrap they collected from a local farmer at a ratio of 80 to 20 to fabricate a plastic blend. Four different biocomposites were created by mixing the fabricated blend with five, 10, 15 or 20 per cent of biocarbon. These biocomposites were then evaluated for their strength, morphology, dimensional stability, and thermal behavior in the temperature range between -50 degrees Celsius and 850 degrees Celsius.

They found that the incorporation of five per cent biocarbon obtained at 500 degrees Celsius and 10 per cent biocarbon at 900 degrees Celsius produced a biocomposite that demonstrated balanced strength, stiffness, and flexibility properties and suitable melt flow behavior – most promising for rigid packaging and 3D printing applications.

“We successfully created biocomposites composed of 95 per cent sustainable input materials, displacing the fossil-based resources,” says Misra. “Furthermore, our biocomposites are potential candidates for industrial uses such as packaging and additive manufacturing. This new research to utilize recycled waste materials to produce biocomposites would be a significant step towards reducing our environmental footprint and achieving the global sustainable development goals.”

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