Mechanical and thermal enhancement of mono- and bilayer PVA/xanthan gum films via cellulose nanofibrils and corona treatment

Abstract

The development of biodegradable materials has intensified as an alternative to petroleum-based polymers, yet achieving suitable properties at a competitive cost remains challenging. This study evaluated mono- and bilayer films of polyvinyl alcohol (PVA) and xanthan gum (XG) incorporating cellulose nanofibrils (CNFs) and subjected to corona treatment. The films were produced by casting and coating and characterized for physical, thermal, chemical, optical, and mechanical properties. In monolayers, CNF promoted structural compaction, reduced solubility, and improved thermal stability, raising degradation onset temperature by 33% and tensile strength by 37% while decreasing elongation at break. In bilayers, CNF increased tensile strength and Young’s modulus but reduced flexibility; corona treatment reversed this effect, enhancing adhesion and elongation at break by 286%. FTIR confirmed hydrogen bonding and corona-induced modifications, while optical analysis showed higher opacity with CNF. The results demonstrate that CNF and corona treatment synergistically improve film performance, supporting applications in sustainable food packaging.