Biodegradable mulch films produced from soy-filled polymer resins

Abstract

Large quantities of plastic waste from mulch films have accrued in the topsoil of agricultural fields across the globe. The costly, time-consuming, and laborious task of removing these films, combined with the slow mineralization rates of traditional plastics used for mulch film has magnified the waste in the last few years. A solution to this issue is to replace single-use plastics with biodegradable plastics. In this study, several byproducts from the soy protein isolate production were blended with biodegradable polymers, including poly(butylene adipate-co-terephthalate) (PBAT) and poly(lactic acid) (PLA). First, a 20 wt% of soy waste was compounded with PLA, PBAT/PLA (a polymer blend), and polyethylene, and then cast extruded into mono-layered films. A combination of soy waste and PBAT/PLA showed promising thermal stability and polymer processability for mulch film applications and thus was selected for further investigation. The weight loss as a function of time in soil environment also shows that the down-selected PBAT/PLA/Soy displayed weight loss within a week in a soil environment while PBAT/PLA (as a control group) remained unchanged. With promising results obtained from this study, a cost-effective biodegradable mulch film that does not require collection post-harvesting would be feasible.