Preparation and characterisation of polyvinyl alcohol/glycerol blend thin films for sustainable flexibility

Abstract

Petroleum-based polymers pose significant environmental challenges, prompting researchers to seek alternatives for decades. The foremost solution to replace petroleum-based packaging lies in bio-based polymers that can degrade with water, soil and the environment. The most common and economical bio-based polymer till to date is polyvinyl alcohol (PVA) but has a limitation of brittleness. The primary objective of this study is to enhance mechanical flexibility, transparency and barrier properties by incorporating glycerol (G) as a plasticiser in a Polyvinyl alcohol (PVA) matrix. The PVA-G blends thin film were prepared through a solution casting processing route with glycerol concentrations varying up to 5%. These modified thin films exhibited exceptional mechanical flexibility, and good optical properties by boasting a transmittance rate exceeding 90%. Compared to pure PVA thin films, the modified versions (PVA-G) demonstrated a significant increase in their water barrier capabilities. Remarkably, the incorporation of 5% glycerol led to a substantial increase in biodegradability, and flexibility, overcoming the brittleness commonly associated with pure PVA thin films. Furthermore, the mechanical properties of the modified thin films exceeded those of pure PVA, indicating an overall enhancement in mechanical performance and tensile strength. The prepared thin films unveil exciting possibilities for utilising these flexible PVA thin films across diverse applications, including flexible food packaging, membranes, biomedical materials, and other industries that require adaptable and pliable materials.