Evaluation of the ageing resistance and lifespan of talc-filled poly(butylene adipate-co-terephthalate)/polylactide (PBAT/PLA) films used for winter potato cultivation

Evaluating the lifespan of aged biodegradable mulch films from the perspective of realistic outdoor climate conditions is a challenge. However, it is worthwhile to determine the changes in their structure and stability. In this study, a talc-filled black poly (butylene adipate-co-terephthalate)/polylactide (PBAT/PLA) biodegradable mulch film was designed and mulched with shallow overburden soil to improve the anti-weathering characteristics of winter potatoes grown in southern China. This study focused on the weather resistance properties of biodegradable talc-filled PBAT/PLA-based mulch films. After 4 months of outdoor service, the elongation at break and tensile strength of talc-filled black PBAT/PLA films remained at 360 ± 250% and 15 ± 2.5 Mpa, respectively, with the number average molecular weight decreasing by 21.4% and the gel content increasing to 10%. Combining the results of microstructure analyses, molecular weight changes, thermodynamic properties, and mechanical and structural changes due to accelerated ageing under different indoor conditions, it was concluded that the maintenance of the mechanical properties of the mulch films could be attributed to the inhibition of random chain-breaking and heavy photo-crosslinking in the plastic film system. Our results using biodegradable films based on crop growth characteristics provide an effective strategy for extending the service life of biodegradable plastics and reducing the cost of biodegradable mulch films. Graphical Abstract