Prediction Model of Photodegradation for PBAT/PLA Mulch Films: Strategy to Fast Evaluate Service Life

Eco-friendly biodegradable PBAT/PLA mulch films are attracting increasing interest in sustainable agricultural production. However, currently, little is known about the service life for the PBAT/PLA mulch films. Herein, PBAT/PLA mulch films are subjected to indoor UV-accelerated degradation (UAD) experiments and field cultivation environment degradation (CED) experiments to systematically investigate the relationship between UAD and CED processes. Results demonstrate that 10 days of indoor UAD treatment corresponds to around 120 days aging under outdoor CED conditions. Using eight PBAT/PLA evaluation indicators (haze, elongation at break, tensile strength, gel content, light transmittance, polydispersity index, M_n, M_w), we established a service life prediction model for PBAT/PLA mulch films based on short-term indoor UAD experiments, which could accurately estimate the long-term service life of the mulch films in the field. In particular, using the haze value, near-perfect correlation (R² = 0.995 for eq. 1 and R² = 0.993 for eq. 2) was found between CED days and UAD days. The establishment of these reliable predictive models for the service lifetime of PBAT/PLA mulch films will avoid the undesirable premature breakdown during crop growth, thus fostering end-user confidence in eco-friendly biodegradable mulch films.