Synthesis of organic bisurea compounds and their roles as crystallization nucleating agents of poly(l-lactic acid)

► Novel inexpensive bisurea (BUr) compounds can be synthesized facilely. ► BUrs can accelerate melt crystallization of poly(l-lactic acid) significantly. ► BUrs act as crystallization nucleating agents of poly(l-lactic acid). ► The accelerating effect depends on the methylene numbers in molecular structure. ► The crystal structure of PLLA remains unchanged in the presence of BUrs.