AMP_04_May_June_2021_Digital_Edition

A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A Y / J U N E 2 0 2 1 1 4 SUSTAINABILITY ‘CIRCULAR’ PLASTIC Scientists at the DOE’s Lawrence Berkeley National Laboratory, Calif., designed a recyclable plastic that can be disassembled at the molecular level, and then reassembled into a different shape, texture, and color repeatedly, without loss of performance or qual- ity. The new material, called poly(di- ketoenamine), or PDK, plastic could be a good alternative to many nonrecyc- lable plastics in use today. The chemicals added to make most plastics useful are tightly bound to their monomers and stay in the plastic even after being recycled. During the re- cycling process, plastics with different chemical compositions are mixed together. When that hodgepodge is melted to make a new material, it is hard to predict which prop- erties it will inherit from the original plastics. This in- heritance of unknown and therefore unpredictable properties has prevented plastic from becoming what many consider the Holy Grail of recycling: a “circu- lar” material whose original monomers can be recov- ered for reuse for as long as possible, or upcycled to make a new, higher quality product. “With PDKs, the immutable bonds of conventional plastics are replaced with reversible bonds that allow the plastic to be recycled more effectively,” says Brett Helms, staff scientist in the lab’s Molecular Foundry. Unlike conven- tional plastics, the monomers of PDK plastic could be recovered and freed from any compounded additives simply by dunking the material in a highly acid- ic soluti on. lbl.gov. FIBER AIDS LIGHTWEIGHTING An international team of research- ers, led by the University of Portsmouth, U.K., developed a biocomposite materi- al using date palm fiber biomass—an agricultural waste—to produce sus- tainable and lightweight applications in the automotive and marine indus- tries. The date palm fiber polycaprolac- tone (PCL) biocomposite is completely biodegradable, renewable, sustainable, and recyclable. In testing the mechan- ical properties, researchers found that the new PCL had increased tensile strength and achieved better low-ve- locity impact resistance than traditional man-made composites. “These lightweight alternatives could help reduce the weight of ve- hicles, contributing to less fuel con- sumption and fewer CO 2 emissions. The sustainable materials can be produced using less energy than glass and carbon fibers and are biodegradable, therefore easier to recycle,” says lead researcher Hom Dhakal. “The challenge is getting consistent, reliable properties. It takes a long time to convince people to use a new class of materials, such as natural fiber reinforced composites for non- structural and structural applications. Meeting these challenges requires fur- ther research and innovation between academic institutions and industry.” www.port.ac.uk . A sample of date palm fiber composite is tested for its mechanical properties. Courtesy of University of Portsmouth. PDK plastics are a “circular” material whose original monomers can be recovered for reuse for as long as possible, or “upcycled” to make a new, higher quality product. Courtesy of Peter Christensen et al./Berkeley Lab. 6K, North Andover, Mass., announced a new center of excellence focused on developing sustainable battery materials for electric vehicles, grid storage, and consumer goods. The company will invest $25 million over the next two years to triple the size of its North Andover facility with 10 UniMelt systems dedicated to developing and producing battery materials . 6Kinc.com. Frontier Airlines, Denver, signed an agreement with Pratt & Whitney for 268 ultra-efficient GTF (geared turbofan) engines to power 134 A320neo family aircraft scheduled for delivery beginning in 2022. Compared to previous-generation aircraft, the GTF engine reduces fuel burn and carbon emissions by 16% and noise footprint by 75% percent, while bringing nitrogen oxide emissions 50% below the regulatory standard. flyfrontier.com. BRIEFS