Environmental impacts of functional fillers in polylactide (PLA)-based bottles using life cycle assessment...

The use of functional fillers added to PLA-based products can be beneficial in terms of cost reduction and properties improvement. The existing life cycle assessment of PLA containers mainly focuses on the greenhouse gas (GHG) emission of PLA material model without fillers, and overlooked environmental impacts of functional fillers and the significant environmental problem-shifting on other indicators. This paper presents a life cycle assessment (LCA) of cooking oil bottles made from PLA, PLA/Fibers and PLA/CaCO₃ considering a wide spectrum impacts, and compares the environmental profile of them based on normalization and weighting analysis. The functional unit was set at 1000 bottles of 900 mL. The system boundary is from cradle to gate, including PLA-based particles production, bottle processing and transportation. The results showed that the contribution of the primary energy demand (PED) index of PLA-based bottles accounted for 159% to 192% of the global warming potential (GWP) index, which may be overlooked in previous studies. Compared to PLA and PLA/Fibers bottles, PLA/CaCO₃ bottles have lower environmental impacts in most categories and the lowest integrated impact index. In terms of PLA/CaCO₃ bottles, PLA particles and electricity contributed the most to energy conservation and emission reduction (ECER) results, accounting for 63.09% and 28.26% to the integrated impacts index, respectively. The results imply that the use of fillers in PLA bottles tends to reduce the environmental impacts, especially calcium carbonate can efficiently minimize environmental impacts of PLA-based bottles. And PED, SO₂ and NO_X indicators ranking above CO₂ should be taken into consideration to avoid the environmental problem-shifting, which can provide valuable reference for the creation of the method of making biodegradable plastic and carbon neutral policies.