Stereocomplexes from Biosourced Lactide/Butylene Succinate-Based Copolymers and Their Role as Crystallization Accelerating Agent

Biosourced co(polyester urethane)s containing different ratios of enantiomeric oligo(L- or D- lactide) (OLLA/ODLA) sequences and oligo(butylene succinate) (OBS) blocks (P(OD(L)LA-b-OBS)) are synthesized. Their stereocomplexation is confirmed by differential scanning calorimetry and X-ray diffraction. The process is efficient independently on the OLA/OBS ratio and for OLLA/ODLA ratios from 2:3 to 3:2. The preformed stereocomplexes show remarkable crystallization accelerating efficiency when melt-blended with a commercial PLLA in amounts from 2.5 to 10 wt%. Spectacular increase in the polyester matrix crystallinity (from 2 up to 42%) and crystallization rate (half-time of ca. 3 min compared to ca. 30 min for the neat PLLA) is observed.