The Stereocomplex Crystallites Improve the Stability of Biodegradable Poly(L-lactic acid)/Poly(D-lactic acid) Melt-Blown Nonwovens

Poly(lactic acid) (PLA) is a biodegradable and eco-friendly polymer that is increasingly being incorporated into various applications in contemporary society. However, the limited stability of PLA-based products remains a significant challenge for their broader use in various applications. In this study, poly(L-lactic acid)(PLLA)/poly(D-lactic acid) (PDLA) melt-blown nonwovens were prepared by melt spinning. The structure, thermal properties, thermal stability, biodegradability and crystalline morphology of the melt-blown nonwovens were investigated. DSC and WAXD confirmed the formation of stereocomplex (SC) crystallites in the PLLA matrix. The storage modulus (G′), loss modulus (G″), and complex viscosity (∣η*∣) of the PLLA/PDLA blend increased with an increase in SC crystallite content. The thermal degradation temperatures of PLLA/PDLA melt-blown nonwovens increased with the incorporation of SC crystallites, and the maximum rate of decomposition increased to 385.5 °C, thus enhancing the thermal stability. Compared with neat PLLA melt-blown nonwovens, the hydrophobicity of PLLA/PDLA melt-blown nonwovens was improved, and WCA increased to 139.7°. The SC crystallites were more resistant to degradation by proteinase K compared to neat PLLA. However, the degradation rate of PLLA/PDLA melt-blown nonwovens remained at a high level. This work provides an effective strategy to obtain high-performance PLLA melt-blown nonwovens.