Preparation, Characterization and Properties of PPC-based Fully Biodegradable Ternary Blends for Sustainable Packaging Application

Abstract

This study aimed to develop fully biodegradable ternary composite films based on poly(vinyl alcohol) (PVA), poly(propylene carbonate)-based polyurethane (PPC-PU), and poly(propylene carbonate) (PPC-X) for sustainable packaging applications. The films were prepared by melt blending pre-plasticized PVA1788 with PPC-PU and PPC-X at varying mass ratios, followed by hot-pressing. A comprehensive set of analyses—including mechanical tests, FTIR, SEM, DSC, TGA, gas permeability, water contact angle, and water absorption measurements—was conducted to evaluate the structure-property relationships. The results demonstrate that PPC-PU serves as both a compatibilizer and a toughener via hydrogen bonding and polar interactions with PPC-X and PVA. The optimal formulation, PVA/PPC-PU/PPC-X (30/30/40 wt%), exhibited a balanced performance: a tensile strength of 14.32 MPa, an elongation at break of 30.29%, a glass transition temperature of 44.6°C, and a thermal degradation onset at 191°C. The films showed moderate hydrophilicity, suitable for humidity regulation in fresh produce packaging. Notably, the composites displayed superior CO₂ and oxygen barrier properties, with the 30/40/30 blend achieving a CO₂ permeability of 5360 cm³·µm/(m²·day) and an O₂ permeability of 1002 cm³·µm/(m²·day). However, water vapor permeability increased due to PVA’s hydrophilicity. Overall, these ternary composites exhibit promising mechanical, thermal, and barrier properties, positioning them as viable and sustainable alternatives to conventional non-biodegradable plastics such as LDPE, PET, and PP, with significant potential to reduce petroleum dependence and promote carbon dioxide valorization.