Researchers make biocomposites from discarded stone

Researchers at The University of British Columbia (UBC) Okanagan are using polymers and natural stone slurry waste to make environmentally friendly stone composites.

The composites are made of discarded materials left behind during the cutting of natural structural or ornamental stone blocks for buildings, construction supplies or monuments.

School of Engineering Professor and Director of UBC’s Materials and Manufacturing Research Institute (MMRI) Abbas Milani said that the re-use of waste material from natural stone production is common in cement, tile and concrete production, but adding the stone slurry to polymers is a new and innovative idea.

He explained that a growing industrial demand for multifunctional biofriendly raw materials is pushing researchers to develop value-added and energy-saving biocomposites and processes.

“Because the slurry is a waste material, it comes at a lower cost for recycled composite production,” Prof Milani said.

Prof Milani and his colleagues recently received UBC eminence funding to establish a cluster of research excellence in biocomposites. The cluster will develop novel agricultural and forestry-based bio and recycled composites to minimise the impact of conventional plastics and waste on the environment.

The powdered stone waste used in the project provides flexibility to the new particulate polymer matrix composite. It can be mixed at different ratios into the finished product through appropriate heat or pressure to meet structural requirements or aesthetic choices, defined by industry and customers.

“This green stone composite can easily be integrated into a variety of applications,” said UBC Research Associate Davoud Karimi. “These composites can be used in decorations and sanitation products ranging from aerospace to automotive applications.”

The researchers varied the amount of stone added to the composites then tested several parameters to determine strength, durability and density along with thermal conductivity. The moulding and mechanical tests were conducted in the Composites Research Network Okanagan Laboratory with collaboration from the MMRI.

The researchers found that adding stone waste to the composites increased the virgin polymer’s strength and durability and proportionally increased the composites’ conductivity based on the amount of stone added.

“The increased strength is important, but the increased conductivity (up to 500%) opens a huge door to several new potential applications, including 3D printing with recycled composites,” Prof Milani said.

“Any time we can divert waste from landfills and generate a product with the potential of economic benefit is a win-win,” he added.

“We hope that these sorts of products, that are carefully designed with the aid of multidisciplinary researchers focused on 3R measures (repairable, re-usable and recyclable), can significantly contribute to the economy of our region and Canada as a whole.”

The research has been published in Composite Structures and Composites Part B: Engineering.

Image credit: ©stock.adobe.com/au/Naletova