Stereocomplex Formation in Polylactide Multiarm Stars and Comb Copolymers with Linear and Hyperbranched Multifunctional PEG

A systematic comparison between graft poly( l‐ lactide) copolymers with different topologies and their ability to form stereocomplexes with poly( D ‐lactide) (PDLA) is performed. Comb and hyperbranched copolymers based on functional poly(ethylene glycol) and poly( l‐ lactide) with molecular weights in the range of 2000–90 000 g mol −1 and moderate molecular weight distributions ( M w / M n = 1.08–1.37) are prepared via the combination of anionic and ring‐opening polymerization. Two “topological isomers,” a linear poly(ethylene oxide)/poly(glycerol) (PEG/PG) copolymer and a branched PEG/PG copolymer are used as backbone polymers. Furthermore, the stereocomplex formation between PDLA and the hyperbranched and comb copolymers containing poly( l‐ lactide) arms is studied. Stereocomplex formation is confirmed by DSC as well as by Fourier transform IR (FTIR) and Raman spectroscopy. magnified image