Material and sample preparation procedure
PLLA (Mw= 1.1 × 105g/mol, Mn= 4.5 × 104g/mol) used in thepresent study was supplied from Mitsubishi Plastic Inc. AmorphousPLLA film were prepared by compression molding at 190◦C for5 min at molten state. Two different thickness PLLA films were pre-pared. The films about 40 m were used for the FTIR measurementand the thick films about 1 mm were used for the DSC and WAXDmeasurement.