Biodegradation and characterization study of compostable PLA bioplastic containing algae biomass as potential degradation accelerator

Abstract This study demonstrated the degradation behavior of poly(l-lactic acid) (PLA)/algae biomass biocomposites under abiotic (58 ± 2 °C) and at thermophilic composting conditions (58 ± 2 °C). In the biodegradation study, laboratory synthesized, custom-made poly(e-caprolactone) (PCL) pellets and its dumbbells were considered as the second bioplastic component in order to develop a comparative data of PLA based biocomposites. In experimental work 1, PLA based biocomposites highlighted that chain scission alone could not produce enough oligomers for microbial assimilation and provided information related to critical molecular weight, which marked the sudden weight loss of materials. In experimental work 2, laboratory synthesized PCL and its biocomposites were used along with PLA based samples for the biodegradation study. This was done to spawn a more precise comparative notion on the biodegradation process of PLA based samples following ASTM International D5338–15. Addition of 5-wt% of deoiled algae biomass in PLA showed an incremental effect on biodegradation of PLA biocomposites. High elemental nitrogen content in the algae biomass accelerated the degradation process in the PLA biocomposites by fueling up the microbial growth. This study will help in designing PLA based biocomposites using algae biomass as well as other nitrogen rich fillers, which might increase the biodegradability of PLA based polymers under different environment.