Wind energy is an increasingly popular form of renewable energy. However, when it’s time to replace the huge turbine blades that convert wind into electricity, disposal is a problem. Now scientists are reporting a new composite resin suitable for making these behemoths that could then be recycled into new turbine blades or a variety of other products, including countertops, car taillights, diapers and even gummy bears.
Researchers will present their findings today at the American Chemical Culture (ACS) Fall Meeting.
“The beauty of our resin system is that at the end of its use cycle, we can dissolve it, and that frees it from whatever matrix it is in. lies so that it can be used over and over again in an infinite loop,” says John Dorgan, Ph.D. who is presenting the work at the meeting. “That’s the goal of the circular economy.”
Made of fiberglass, wind turbine blades can be half the size of a soccer field. Although some companies have found ways to recycle fiberglass into lower value materials, most discarded blades end up in landfills. And the disposal problem is likely to get worse. “Bigger wind turbine blades are more efficient, so companies keep making bigger and bigger ones,” says Dorgan. “Often wind farms will replace wind turbine blades before the end of their life, because parks can generate more electricity with larger blades.”
Dorgan and his colleagues at Michigan State University made a new turbine material by combining glass fibers with a plant-based polymer and a synthetic polymer. Panels made from this thermoplastic resin were strong and durable enough to be used in turbines or coaches. The researchers dissolved the panels in fresh monomer and physically removed the glass fibers, allowing them to re-melt the material into new products of the same type. Importantly, the recast panels had the same physical properties as their predecessors.
In addition to the new wind turbine blades, the new resin could be used for a variety of other applications . By mixing the resin with different minerals, the team produced society stone that can be crafted into household objects, such as countertops and sinks. “We recently made a bathroom sink with society stone, so we know it works,” says Dorgan. Researchers could also crush the recovered material and mix it with other plastic resins for injection molding, which is used to make items like laptop sleeves and power tools.
The material could even be recycled into more valuable products. Digestion of the thermoplastic resin in an alkaline solution released poly (methyl methacrylate) (PMMA), a common acrylic material for windows, car taillights and many other content items. Raising the temperature of digestion converted the PMMA into poly (methacrylic acid), a super absorbent polymer used in diapers. Alkaline digestion also produced potassium lactate, which can be purified and made into candies and sports drinks. “We salvaged food-grade potassium lactate and used it to make gummy candies, which I ate,” Dorgan says.
Now that the researchers have demonstrated that the resin has physical properties suitable for wind turbines, they hope to manufacture medium-sized blades for field trials. “The current limitation is that there are not enough bioplastics that we use to satisfy this market, so there must be a considerable amount of production coming online if we really want to start making wind turbines from these. materials”, Dorgan Remarks.
And is there a “yuck factor” involved in eating candy that was once part of a wind turbine? Dorgan doesn’t think so. “A carbon atom derived from a plant, like corn or grass, is no different than a carbon atom from a flamable fossil,” he says. “It’s all part of the global carbon cycle, and we’ve shown that we can move from biomass on the ground to sustainable plastic materials and back to food.”
The scholars acknowledge funding from the David L. and Denise M. Lamp Endowment.