摘要 |
A stereospecific poly(lactic acid) is isotactic poly(lactic acid) having a number average molecular weight ranging from 10,000 to 200,000 grams per mole, with, on average, an equal number of poly (R) and poly (S) blocks where each block contains an average of 5 to 50 monomer units. Product was prepared by polymerizing rac-lactide in the presence of racemic catalyst consisting of:and the corresponding S-enantiomer or in the presence of racemic catalyst consisting of:and the corresponding S-enantiomer, wherein R is C1-C4 alkyl which is straight chain or branched. |