Effect of Solvent Combination on Electrospun Stereocomplex Polylactic Acid Nanofiber Properties

Polylactic acid (PLA) has been known as bio-based polymer for the development of bioplastic with promising properties such as biodegradable, biocompatible, non-toxic, and renewable. However, its low thermal properties have limited its applications. Thus, in this study stereocomplex PLA (sc-PLA) is investigated with the aim to improve thermal properties by mixing poly L-lactic acid (PLLA) and poly D-lactic acid (PDLA) in solution blend combination via electrospinning. The electrospun sc-PLA fiber is prepared in combination of chloroform (CHCl3),N,N-dimethylformamide, and hexafluoroisopropanol (HFIP). The effect of solvents in the properties of sc-PLA is analyzed using Fourier-transform infrared spectroscopy and X-ray diffraction (XRD) to understand chemical interaction between PLLA and PDLA. Differential scanning calorimetry and thermo gravimetric analyzer is used to understand the thermal properties of sc-PLA. It is found that the optimum solvent combination for sc-PLA nanofiber is CHCl3/HFIP 9:1 with the smallest nanofiber diameter 39.7 nm and the melting point improved by 47 degrees C compared with neat PLA due to stereocomplexation between PLLA and PDLA.