Development of Biodegradable Films for Sustainable Agricultural Applications by Using Thermoplastic Potato Starch and PBAT

Abstract

The transition toward biodegradable agro-films demands scalable formulations that match the performance of commodity plastics while avoiding toxic reagents. Here we report a 100% solvent-free, twin-screw-extruded TPS-PBAT blend simultaneously compatibilized with citric acid, glyceryl monostearate, and PEG-400, a combination not previously explored. The ternary compatibilizer yielded a macroscopically uniform blend, doubled stiffness (Young´s modulus (17.3 ± 0.9) MPa vs. (8.2 ± 0.4) MPa for TPS) and stabilized surface hydrophobicity (contact angle (63 ± 6) ° for ≥ 25 s) while preserving transparency and achieving > 99% UV-B/C blocking. PBAT incorporation did not sacrifice biodegradability: both films reached 87% mineralization in industrial compost after 100 days and 62% in soil after 30 days, with no ecotoxicity toward tomato seedlings. Thermogravimetric analysis revealed partial TPS-PBAT miscibility (~3 wt%) promoted by the compatibilizer trio, also confirmed by SEM. Urea-loaded films released 80% of the nutrient in 13 days and then plateaued, demonstrating suitability as active, bio-disintegrable seedling trays. This work closes the gap between laboratory-scale TPS blends and industrial needs by introducing a green multicomponent compatibilization route, providing quantitative structure–property relationships, and validating field-relevant functionality. The process relies on standard extruders, enabling straightforward global adoption in the agricultural plastic sector.