Chemical engineers produced a new resin for wind turbine blades that can convert into other materials for various products. (Image Credit Made From The Sky/Unsplash)
Many wind turbine blades typically last twenty years before being discarded and sent to landfills. Recycling these into less-valuable materials instead could prove beneficial in the long run. University of Michigan engineers produced a new resin material, which can be recycled into another blade after decommissioning the original. Otherwise, the resin may also be downcycled for various applications, such as gummy bears, cell phone cases, car tail lights, power tools, and countertops.
Turbine blades measure approximately 170 feet long. Meanwhile, offshore wind farms are working toward deploying larger wind turbines equipped with longer blades to harvest more energy. These must be decommissioned if they get damaged or reach their end of life.
However, two challenges arise from recycling these blades. For starters, the blades are difficult to disassemble and move around. The other problem is that they're made of fiberglass bonded with a polymer resin to meet performance expectations. That material is recyclable, but the end product doesn't hold much value. "The main problem is: it's simply uneconomic to do it," said John Dorgan, a professor of chemical engineering and materials science at Michigan State University, who developed the resin. "It's cheaper to just bury it in the ground than it is to reprocess it into something useful."
So Dorgan and his team mixed a plant-derived polymer called polylactide and methyl methacrylate (MMA), a synthetic monomer, to create the resin. Afterward, vacuum pressure moved the liquid mixture through glass fibers, causing the resin to harden. As a result, this process produced tough and durable fiberglass panels for large structures like turbines and cars.
The engineers then explored various techniques to recycle the panels. One option involved breaking up the panels into small pieces and depositing another polymer to form a plastic, which can turn into products via injection molding. While these may have computer casing and other applications, the plastic wouldn't be very valuable. In the second method, they created strong panels by using the leftover ones. In this case, the team drenched them with the MMA monomer, causing the resin to dissolve, and removed the glass fibers. The team also used this liquid to create new fiberglass panels with similar physical properties as the originals.
The team placed the resin in an alkaline solution to produce potassium lactate. (Image Credit: Dan Cristian Pădureț/Unsplash)
Even then, the remaining resin could be used for other applications. So the resin underwent chemical reactions to form substances. In this case, the process created polymethyl methacrylate, also known as plexiglass. The engineers also exposed the resin to high temperatures and created polymethacrylic acid, commonly used in diapers. They also placed it into an alkaline solution, producing potassium lactate. This, in turn, can undergo purification to create gummy bears and sports drinks. However, Dogan believes this should be utilized for recycling turbine blades rather than homemade candy. "We recovered food-grade potassium lactate and used it to make gummy bear candies, which I ate," said Dorgan.
The researchers want to use their newly formed resin to build moderately sized blades for field testing. "The current limitation is that there's not enough of the bioplastic that we're using to satisfy this market," said Dorgan. "There needs to be considerable production volume. If we're going to actually start making wind turbines out of these materials."
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