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Each year, the world produces roughly 100 million tons of flexible multilayer plastic packaging \u2014 materials that keep food fresh and pharmaceuticals safe from moisture and oxygen. Yet most of these plastics are nearly impossible to recycle due to their complex, chemically incompatible layers.<\/p>\n
Researchers in Michigan State University\u2019s School of Packaging and College of Engineering<\/a>, in collaboration with the Pacific Northwest National Laboratory, have developed a scalable approach to address this challenge. Supported by a $1.7 million grant from the U.S. Department of Energy, the team designed polyester-based multilayer films that perform comparably to commercial packaging while offering potential for both mechanical and chemical recycling.<\/p>\n One of the plastics industry\u2019s biggest challenges is making previously unrecyclable plastics recyclable. Led by Professor Muhammad Rabnawaz, Ph.D.<\/a>, the research team set out to re-engineer multilayer structures so they could enter both recycling streams without compromising performance.<\/p>\n The result is a new class of polyester multilayer plastics composed of 80 to 100 percent polyester. The films combine PET (polyethylene terephthalate) for strength and clarity, with PBAT or PBS for sealability and EVOH (ethylene-vinyl alcohol) or PGA (polyglycolic acid) for barrier protection.<\/p>\n By keeping the chemistry within the same polymer family, at least 80 percent, the researchers achieved structures that remain compatible during recycling.<\/p>\n The team produced two main designs using standard cast film melt co-extrusion: a PGA-based trilayer (PET\/PGA-PBAT\/PBAT) and EVOH-based four-layer films (PET\/EVOH\/PET\/PBS or PET\/EVOH\/PET\/PBAT). This indicates the process can be scaled using existing industry equipment<\/a>.<\/p>\n Rabnawaz, director of the NSF Center for Plastic, Paper and Hybrid Packaging End-of-Life Solutions (C3PS), described the work as a balance between performance and sustainability.<\/p>\nNew multilayer design<\/h4>\n
Performance comparable to commercial films<\/h4>\n