Understanding the Biological Degradation of Home Compostable Multilayer Packaging

Understanding the Biological Degradation of Home Compostable Multilayer Packaging

October 4, 2023, 1:00 PM EST – 2:00 PM EST

Speaker: Evan M. White, Ph.D., New Materials Institute, The University of Georgia
Moderator: Todd Fayne, PepsiCo

Overview

A systematic approach using rounds of respirometry and disintegration testing was employed to design for industrially compostable and home compostable multilayer packaging (MLP). The study incorporated two rounds of thermophilic composting (58°C) examining various film chemistries, thicknesses, adhesives, inks, and metallization variables. Respirometry and disintegration photography data from thermophilic composting revealed 12 monolayer films and MLP structures with greater than 90% carbon mineralization within 90 days, half the time allotted for industrial composting certification. These data also provided insights for MLP structure design for materials tested under mesophilic (35°C) and psychrotrophic (20°C) home composting conditions, demonstrating one structure achieving >97% carbon mineralization in 6 months of composting at 20°C. Thermal properties of the MLP structures have been studied using TGA and DSC, and water vapor transmission rates have been determined for both industrial and home compostable monomaterial films and MLP with many examples yielding water vapor transmission rates <1 g/m2·24h. At 20°C home composting conditions, the laminations of regenerated cellulose with either poly(hydroxy alkanoates) or poly(butylene succinate-co-butylene adipate) yielded faster carbon mineralization and disintegration than either regenerated cellulose or the polyester monomaterial films alone, illustrating an acceleration in degradation outcomes with complex MLP structures when compared to monomaterials.