Morphological analysis and non-isothermal cold crystallization kinetics of sulfur-activated polylactic acid composites

Sulfur-activated PLA composites have been prepared and characterized to determine the effects of various sulfur contents on their structure, morphology, and thermal characteristics. Wide-angle X-ray diffraction (WAXD) profiles of the composites showed that sulfur has a non-significant effect on the lattice structures of PLA. Polarized optical microscope (POM) showed an increase in the nucleation of several PLA spherulites in the presence of sulfur. Scanning electron microscopy (SEM) revealed that sulfur influences the arrangement of PLA .The crystallization kinetics and thermal stability of the composites by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were appreciably improved in the presence of sulfur. The Avrami model was used to analyze the thermal data. The theories of Kissinger and Arrhenius were used to calculate the activation energy (ΔE). A faster crystallization rate and higher ΔE values were observed for the sulfur-activated composites compared to pristine PLA.