Biobased Triesters as Plasticizers for Improved Mechanical and Biodegradable Performance of Polylactic Acid Fibrous Membranes as Facemask Materials

The COVID-19 pandemic has incredibly escalated the use of petroleum-based disposable facemasks, posing a significant environmental burden. In response, polylactide acid (PLA), a biobased and biodegradable aliphatic polymer, has been considered a potential alternative. However, applications of PLA in facemask materials are hindered by its inherent brittleness, poor toughness, and slow degradation rate in the environment. Addressing these challenges, this study explored the use of two biobased triesters as green plasticizers to improve PLA fibrous membranes with desired mechanical properties and biodegradability. PLA and the plasticizers were mixed and electrospun into the fibrous membranes. The influence of two plasticizers in varied contents on the filtration efficiency, morphology, thermal behavior, mechanical properties, and degradation rate of the PLA membranes is systematically investigated. The findings reveal that the proper addition of these plasticizers (7% content) not only effectively lowered the glass transition and cold crystallization temperatures of PLA membranes from 65 to 52 °C and from 78 to 70 °C, respectively, without compromising the filtration performance but also significantly enhanced the material's toughness, as evidenced by the increased tensile strength from 0.44 to 1.08 MPa and the elongation at break from 1.32% to 12.53%. Furthermore, the plasticized PLA membranes exhibited an enzymatic degradation rate of 34.18% at 50 °C after 96 h, a more than 2-fold increase compared to that of pure PLA. These advancements in this work contribute to the development of high-performance and eco-friendly filtration materials, offering a sustainable solution to the environmental challenges posed by conventional facemasks.