Novel Biodegradable Poly (Glycolic Acid) Dual-Layer Packaging System Using Spray Coating

Polymer films are essential barriers for food and consumer packaging, but because they are durable, they contribute to accumulating waste that infiltrates ecosystems, enters food chains as microplastics, and overwhelms disposal systems. This research responds by developing a biodegradable packaging system designed to reduce plastic pollution and improve environmental sustainability. A dual-layer design packaging system incorporating a cellulose nanofibril (CNF)-reinforced paper substrate spray-coated with a poly(glycolic acid) (PGA) outer layer is designed to enhance barrier performance. The approach involves spray coating CNF onto the paper substrate to effectively fill surface pores, followed by an additional spray coating of PGA to create a dense, uniform layer. This dual-layer system demonstrated notable improvements, including a substantial oxygen barrier performance to approximately 1.6 cm³/(m²·24 hour), improved surface smoothness, reduced roughness from 3.8 µm to 1.3 µm, maintained good thermal stability, and enhanced hydrophobicity, with water contact angles around 60°, indicating improved moisture resistance. Scanning electron microscopy further confirmed these improvements by revealing a uniform, dense PGA coating layer with robust interfacial adhesion to the CNF-treated paper substrate. These advancements present a viable biodegradable packaging alternative aligned with circular economic principles, offering opportunities for industrial implementation.