Biodegradable and antioxidant lignin-adsorbed polylactic acid microparticles for eco-friendly primary microparticles

The severity of environmental and ecological pollution caused by microplastics has become a prominent global concern. In this study, we prepare biodegradable microplastics to replace primary microplastics used as solid raw materials in personal care and cosmetics, synthesizing them using eco-friendly materials, including polylactic acid (PLA, base material), decyl glucoside and lignin (co-surfactants). Employing a solvent evaporation method, uniform spherical microparticles with an average diameter of approximately 5.5 μm are produced. They are potentially harmless to humans and the environment. During the process, lignin adsorbs onto the surface of PLA through non-covalent interactions, forming Lig@PLA microparticles. Additionally, the aqueous solution used in the process can be reused at least four times, presenting both economic and environmental benefits. The Lig@PLA microparticles exhibit approximately 1.3-fold faster biodegradation and 163 times higher antioxidant activity compared to neat PLA due to the presence of lignin on the PLA surface. Consequently, the biodegradable microplastics developed in this study demonstrate potential for use as solid raw materials in personal care products and cosmetics and offer a promising solution to mitigate environmental and ecological pollution by microplastics.