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A new leaf-inspired design brings bioplastics to the big leagues. Society has long struggled with petroleum-derived plastic pollution, adn awareness of microplastics’ detrimental effects on food and water supplies adds further pressure [[1]]. In response, researchers have been developing biodegradable versions of customary plastics, or “bioplastics” [[2]] [[3]]. However, current bioplastics face challenges as well: Current versions are not as strong as petrochemical-based plastics and they only degrade through a high-temperature composting system.Enter researchers at Washington University in St. Louis, who have solved both problems with inspiration from the humble leaf. Long before plastic, humans wrapped their food in leaves, which easily biodegrade due to an underlying structure of cellulose-rich cell walls. Chemical engineers decided to introduce cellulose nanofibers to the design of bioplastics.”We created this multilayer structure where cellulose is in the middle and the bioplastics are on two sides,” says Joshua Yuan, a professor and chair of energy, environmental, and chemical engineering at the McKelvey School of Engineering. Yuan is also director for the National Science Foundation-funded Carbon Utilization Redesign for Biomanufacturing (CURB) Engineering Research Center. “In this way, we created a material that is very strong and that offers multifunctionality.”
The technology emerged from working with two of the highest production bioplastics today. In a study published in *Green Chemistry* earlier this year, Yuan and colleagues used a variation of their leaf-inspired cellulose nanofiber structure to improve the strength and biodegradability of polyhydroxybutrate (PHB), a starch-derived plastic; they further refined their technique for polylactic acid (PLA), as detailed in a new paper in *Nature Communications*.
The plastic packaging market is a $23.5 billion industry dominated by polyethylene and polypropylene. The researchers’ optimized bioplastic, called Layered Ecological Advanced Functional Film (LEAFF), turned PLA into a packaging material that is biodegradable at room temperature. Additionally, the structure allows for properties such as water and air permeability, and it is indeed printable, which reduces the need for additional labels.
“This is a big step forward for bioplastics,” says Chunhua Yao, a postdoctoral researcher and first author of the study.”As LEAFF is made from renewable resources and is biodegradable, it offers a sustainable alternative to traditional plastic packaging.”