Water-soluble and environmentally friendly polyvinyl alcohol/straw aerogel for sustainable packaging

Abstract

The packaging industry is transitioning towards sustainability in response to growing environmental concerns and evolving consumer expectations. While biodegradable packaging offers promise, issues such as potential microplastics and uncontrolled degradation hinder its widespread adoption as a perfect solution. Leveraging the water solubility of polyvinyl alcohol (PVA) and agricultural and forestry waste, i.e. straw, we demonstrated a PVA/gelatin/straw aerogel using ice-templating freeze-drying and solid state shear milling (S³M) technologies for packaging. The increased porosity of the aerogel enhances specific surface area of PVA, facilitating better interaction with the environment. Furthermore, the inclusion of biomass fillers reduces the phase domain size of PVA, improving water solubility. Gelatin further refines the pore structure, enhancing mechanical properties by providing physical crosslinking points. With an optimized composition, the aerogel achieves a compressive modulus of 0.96 MPa, meeting the strength criteria for polystyrene foam packaging according to QB/T 1649–1992 standards. Importantly, both the aerogel and its aqueous solution demonstrate non-toxicity and environmental friendliness. This study not only presents a series of eco-friendly aerogels but also explores novel applications for PVA in environmentally sustainable packaging.