Method of producing stereocomplex PLLA / PDLA

摘要

Method of producing a stereocomplex polymer PLLA / PDLA 40-60 / 60-40, a number average molar mass of at least 15,000 Dalton, comprising the steps of: a) polymerizing mass LL lactide optical purity of at least 98%, preferably at least 99.5%, even more preferably at least 99.8% to form substantially free PLLA lactide insertion configuration D having an average molecular mass (Mn) greater than 70,000 Dalton; b) polymerizing the lactide mass DD optical purity of at least 98%, preferably at least 99.5%, even more preferably at least 99.8% to form substantially free PDLA insertion lactide L configuration having an average molecular mass (Mn) greater than 70,000 Dalton; c) mixing in the absence of solvent and PDLA PLLA obtained in steps a) and b) in proportions of 40- 60 / 60-40 in the presence of the initial catalyst system used in steps a) and b) and optionally in the presence of L-lactide and D-lactide the unconverted, to a temperature above the melting temperature of the polylactide, without exceeding 250 ° C; d) Optionally desmonomerizar the stereocomplex polymer PLLA / PDLA obtained e) and recovering the stereocomplex Granular PLLA polymer / PDLA mass average molar number 15,000 Dalton and preferably 80,000 Dalton obtained.