Biodegradation of Poly(Lactic Acid) Biocomposites under Controlled Composting Conditions and Freshwater Biotope

Abstract

The influence of additives such as natural-based plasticiser acetyl tributyl citrate (ATBC), CaCO3 and lignin-coated cellulose nanocrystals (L-CNC) on the biodegradation of polylactic acid (PLA) biocomposites was studied by monitoring microbial metabolic activity through respirometry. Ternary biocomposites and control samples were processed by a twin-screw extruder equipped with a flat film die. Commonly available compost was used for the determination of the ultimate aerobic biodegradability of PLA biocomposites under controlled composting conditions (ISO 14855-1). In addition, the hydro-degradability of prepared films in a freshwater biotope was analysed. To determine the efficiency of hydro-degradation, qualitative analyses (SEM, DSC, TGA and FTIR) were conducted. The results showed obvious differences in the degradation rate of PLA biocomposites. The application of ATBC at 10 wt. % loading increased the biodegradation rate of PLA. The addition of 10 wt.% of CaCO3 into the plasticised PLA matrix ensured an even higher degradation rate at aerobic thermophilic composting conditions. In such samples (PLA/ATBC/CaCO3), 94% biodegradation in 60 days was observed. In contrast, neat PLA exposed to the same conditions achieved only 16% biodegradation. Slightly inhibited microorganism activity was also observed for ternary PLA biocomposites containing L-CNC (1 wt.% loading). The results of qualitative analyses of degradation in a freshwater biotope confirmed increased biodegradation potential of ternary biocomposites containing both CaCO3 and ATBC. Significant differences in the chemical and structural compositions of PLA biocomposites were found in the evaluated period of three months.

The Influence of Additives and Environment on Biodegradation of PHBV Biocomposites

“…In our previous study [ 48 ], we reported the similar dependence of the influence of ATBC, L-CNC, and CaCO 3 additives on the biodegradation potential of PLA. The synergistic effect of ATBC/CaCO 3 on the biodegradation rate PLA has been observed.…”

“…Based on the results, all material variants that accomplished the requirements of EN 13432 standard for packaging recoverable through composting can be stated. In our previous study [48], we reported the similar dependence of the influence of ATBC, L-CNC, and CaCO3 additives on the biodegradation potential of PLA. The synergistic effect of ATBC/CaCO3 on the biodegradation rate PLA has been observed.…”

“…The plateau phase (which represents the end of biodegradation) is for the PHBV/ATBC/CaCO3 ternary composite achieved in 57 days, and for PHBV/ATBC in 65 days. On the contrary, the biodegradation for the same combination of additives in PLA bio-composites was still unfinished after 75 In our previous study [48], we reported the similar dependence of the influence of ATBC, L-CNC, and CaCO 3 additives on the biodegradation potential of PLA. The synergistic effect of ATBC/CaCO 3 on the biodegradation rate PLA has been observed.…”

End of Life of Biodegradable Plastics: Composting versus Re/Upcycling

“…Temperature is the first important limiting parameter, since only above PLA glass transition temperature (55 °C) the increased flexibility of the chains facilitates the accessibility to chemical and biological degradation. [11] So, PLLA does not degrade at mesophilic temperatures (25 and 37 °C), while at 60 °C its degradation degree reaches 90 % within 120 days. [12] For this reason, PLA is not suitable for home composting degradation.…”

Water-soluble polyvinyl alcohol composite films with nanodiamond particles modified with polyethyleneimine

“…1 At present, mature biodegradable plastic films mainly include polylactic acid, 2 polycaprolactone 3 and biopolyesters, 4 but they generally have the shortcomings of long degradation cycles and incomplete degradation. 5,6…”