Abstract Poly(lactic acid) (PLA) has great potential in the plastic packaging industry due to its biodegradability, versatility, and good performance. PLA compounding with different biobased materials to enhance the flexibility and biodegradability of PLA-based packaging materials has attracted growing attention. Fungal biomass (FB), as a biological and eco-friendly by-product stream from fermentation processes, can be a valuable blending component in PLA-based biocomposites. Therefore, in this study, 10 and 20 wt% of fungal biomass (FB), defatted fungal biomass (DFB), and fungal cell wall (FCW), as promising biobased materials, were added to PLA plasticised with 10 wt% triethyl citrate (TEC) to fabricate biocomposites using the melt compounding technique. Our research focused on how the addition of fungal biomass and its fractions affected the mechanical and thermal properties, as well as the structure of PLA-based blends. These additions did not increase the strength of the biocomposites, but they did improve flexibility compared to regular plasticised PLA. The crystallisation of plasticised PLA samples blended with FB and DFB began at lower temperatures than neat PLA, plasticised PLA, and plasticised PLA blended with FCW. The addition of fungal biomass and its fractions, particularly at 20 wt%, accelerated the biodegradation of PLA-based composites. Neat PLA and plasticised PLA degraded slowly in soil and retained most of their mass, whereas PLA-based blends containing FB and its fractions degraded significantly faster. It can be concluded that fungal biomass is a promising candidate for improving the flexibility of PLA blends and facilitating their biodegradation in a natural soil environment.
Asadollahzadeh et al. (Fri,) studied this question.