Construction is one of the largest sources of greenhouse gas emissions, so finding new materials and methods is an important goal. Researchers at Flinders University have now developed a new type of polymer, made from industrial waste, that can be made into building bricks that bond together without the need for mortar.
Concrete is an extremely versatile material, but the production of cement alone is responsible for 8% of all carbon dioxide emissions caused by humans. That huge footprint can be reduced by finding ways to incorporate waste materials such as wood or old tires into the mix, using different binders, or developing alternative materials altogether.
The new study explores one such option. The team had previously developed polymers made mostly of sulfur left over from industrial processes, which could be used to capture heavy metal contamination or more sustainable fertilizers. Now, these polymers have been put to serve as more environmentally friendly building blocks.
The polymer is made by mixing sulfur with different proportions of canola oil and dicyclopentadiene (DCPD). Sulfur and DCPD are both byproducts of petroleum refining that currently go waste, while canola oil can be obtained from kitchen waste. The polymer is heated, molded and cured into bricks, the whole process consuming much less energy than cement production.
But what’s really impressive is how these bricks are glued together, essentially acting as their own mortar without the need for another adhesive. In tests, bonded bricks resist shear forces better than superglue.
“An amine catalyst is sprayed onto the surface,” Professor Justin Chalker, corresponding author of the study, told New Atlas. “The catalyst causes the SS (sulfur-sulfur) bond in the brick to rearrange and bind the two bricks together. The catalyst is only needed to initiate the reaction, and it evaporates from the bricks after bonding.”
The team says the bricks are also lightweight, and resistant against water, acid and other weather conditions, even more so than traditional bricks and concrete. In other tests, the researchers added carbon fiber to the polymer, and found that the resulting bricks were about 16 times stronger.
While further development is needed, the Flinders team is collaborating with Clean Earth Technologies to work towards scaling up polymer bricks for potential commercialization.
The research was published in the journal Macromolecular Chemistry and Physics,
Source: Flinders University