Effect of Arrangement of L ‐Lactide and D ‐Lactide in Poly[( L ‐lactide)‐co‐( D ‐lactide)] on its Resistance to Hydrolysis Studied by Molecular Modeling

Abstract Molecular modeling is used to explain how the resistance of poly[(L‐lactide)‐co‐(D‐lactide)] to hydrolysis is affected by the percentages of L‐ and D‐lactide and their arrangements in blocks or random arrangements in the polymer. Previous studies on improving the hydrolysis resistance of PLA have involved forming either poly(L‐lactide)/poly(D‐lactide) (PLLA/PDLA) polyblends or copolymers of L‐ and D‐lactide. In this study, molecular modeling was used to study the hydrolysis resistance of PLA containing various arrangements of L‐ and D‐lactide in the polymers. PLA copolymers are found to have less resistance to hydrolysis than a PLLA/PDLA polyblend having the same percentages of L‐ and D‐lactide because a polyblend can form more stereocomplexes, which is the most stable structure PLA can form. magnified image