Impact of aromatic sulfonate derivative on the crystallization, thermal resistance, and hydrolytic properties of poly(lactic acid)

The thermal, crystallization kinetics and hydrolysis properties of poly(lactic acid)‐based blends containing different concentrations of 5‐dimethylthioisosulfate salts (LAK) were systematically investigated and compared with those of poly(lactic acid) (PLA). PLA/LAK blends were prepared by melt blending method‐using LAK as a nucleating agent of PLA. During the isothermal crystallization process, the morphology of PLA crystal in the neat PLA and PLA/LAK blends showed spherical crystals. With an increase in the concentration of LAK, the nucleating density of the PLA spherulites increased and the size of the PLA spherulites decreased. Differential scanning calorimetry indicates that after the addition of LAK, both the crystallinity and crystallization rate of PLA have been enhanced. In situ X‐ray diffraction analysis also shows that the sample exhibits the same crystal structure as neat PLA and continues to strengthen, indicating that LAK enhances the crystallization properties of PLA. Moreover, the crystallinity of PLA increased and crystal size of PLA decreased with the increase in the LAK content. The Vicat softening temperatures of PLA/LAK blends increased, so the heat resistance improved. Through hydrolysis testing under identical conditions, the PLA/LAK blends exhibits better hydrolytic stability.