Biodegradable and Multifunctional PBAT/Lignin Mulch Films for Green Agriculture

The eco-friendly poly(butylene adipate-co-terephthalate) (PBAT)-based mulch film has become an alternative to traditional polyethylene (PE) mulch films. However, the integration of antibacterial, UV resistance, and high mechanical properties into the PBAT mulch film remained challenging. Herein, two degradable materials, PBAT and alkali lignin (AL), were used as degradable materials under hot pressing to obtain a mulch film. PBAT/AL mulch films performed excellently when 20 wt % AL was added. The composite film (PBAT/AL20) exhibited an excellent tensile stress of 22.41 MPa and an elongation at break of 252.35% after prestretching. The excellent mechanical property was attributed to the hydrogen-bonding interactions between the AL and PBAT molecular chains. Meanwhile, the PBAT/AL20 demonstrated good oxygen permeability (4653 cm3/m2·24 h·0.1 MPa), antibacterial activity, and low light transmittance (0.06% in low-wavelength regions). Outdoor tests showed that PBAT/AL20 had superior degradation properties and that the film could reduce mass degradation by 84.27% within 180 days. This work provides a sustainable strategy for designing films with high performance and promotes the development of eco-friendly alternatives to traditional PE mulch films.