Nonisothermal crystallization and compatibility performances of poly(d-lactide) and poly(l-lactide) blends modified with poly(butylene succinate)

Abstract This study investigates the nonisothermal crystallization and compatibility behavior of poly( d -lactide) (PDLA) and poly( l -lactide) (PLLA) blends modified with varying amounts of poly(butylene succinate) (PBS), ranging from 0 wt% to 50 wt%. When the PBS content reaches 30 %, the PDLA/PLLA and PBS composites exhibit partial miscibility, as confirmed by differential scanning calorimetry (DSC), X-ray diffraction (XRD), and tensile tests. The addition of PBS significantly influences crystallization kinetics, promoting the formation of stereocomplex (SC) crystals in the PDLA/PLLA blends. DSC analysis at various cooling rates reveals that PBS facilitates SC crystal formation and enhances nucleation, particularly at 30 % PBS content, although the growth rate of SC crystallization slows beyond this point. The nonisothermal crystallization behavior also indicates that slower cooling rates reduced homocrystal (HC) formation and increased SC crystallization, demonstrating that cooling rate played a crucial role in crystallization kinetics. Mechanical property testing indicates that the addition of PBS increased the elongation at break of PDLA/PLLA blends. These effects were most pronounced at 30 % PBS content, suggesting that both PBS content and cooling rate could be optimized to enhance the thermal and mechanical properties of PDLA/PLLA blends for advanced applications.