Triggering biodegradation of PLA and PBAT blend films by microembossing

Abstract In the present work, mechanical embossing with microstamps is used to support biodegradation of PLA/PBAT blends. Films of PLA/PBAT are modified by a microembossing process, using metallic stamps with different surfaces. Subsequently, biodegradation is carried out by incubation with Bacillus subtilis DSM 10. The biodegradation efficiency is evaluated through comparative LSM, WLI, mass loss measurements, as well as ATR-FTIR, Raman microscopy, XRD, REM, DSC and EDX before and after the bioegradation process. Results show that the structuring process leads to a significant increase in the degradation rate of the investigated PLA/PBAT blend. The results can be explained by a relative enrichment of PBAT in the near-surface region after degradation, indicating that the PLA component is preferentially degraded through enzymatic cleavage and subsequent microbial metabolization. The findings further demonstrate that the structure-modified surface enables a deliberately tunable PLA/PBAT film interaction with water: the surface exhibits hydrophobic static wettability alongside a controllable pinning effect during use, while a marked improvement in biodegradation is achieved when brought in contact with microorganisms. Mechanical structuring thus represents a simple, chemical-free, and industrially scalable approach to controlling this dual behavior.