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

Abstract

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 confi rmed by DSC as well as by Fourier transform IR (FTIR) and Raman spectroscopy.

Configurational Molecular Glue: One Optically Active Polymer Attracts Two Oppositely Configured Optically Active Polymers

“…In the case of PLA, the mechanical performance, thermal/hydrolytic degradation-resistance of stereocomplexed materials are higher than those of constituent polymers, L-PLA and D-PLA11121314151617. A variety of stereo block343536373839404142434445464748495051, star-shaped5253545556575859606162636465, star-shaped stereo block PLAs6667686970 were synthesized, and the effects of stereo block and star-shaped or branching architectures on crystallization were extensively investigated and found to have crucial effects on stereocomplex (SC) and homo-crystallization behavior.…”

Maintaining Structural Stability of Poly(lactic acid): Effects of Multifunctional Epoxy based Reactive Oligomers

“…The resultant structures may be branched and can thus affect the crystallization kinetics of the stereocomplex crystals [31]. As seen from Figure 12, the stereocomplex melting endotherm is observed in all the blends.…”

Branched aliphatic polyesters by ring-opening (co)polymerization

“…In most cases, the synthesis is accomplished by applying a "corefirst" approach, performing the ring-opening polymerization of a cyclic ester starting from a multifunctional branched polymer (typically a branched polyether or polyester) used as an A c c e p t e d M a n u s c r i p t 31 initiator. One of the most frequently used branched polyethers used as a macroinitiator is polyglycidol [127][128][129], containing multiple hydroxyl groups. Scheme 16 shows the principle of this strategy.…”

“…This is in agreement with the expectation that the crystallization of the oligo-LLA chains is only possible above a certain degree of polymerization of the attached arms. To investigate the host-guest properties of the starshaped block copolymers, extraction studies in the two-phase chloroform/water system have been carried out with water-soluble dyes (methyl orange and rose bengal).In another work, Frey's group used a branched polyglycidol/poly(ethylene oxide) copolymer as a macroinitiator for L-lactide polymerization[129]. Star polymers with polylactide arms al.…”