Published : 2021-01-15

Stereocomplexation of polylactides containing ionic liquid end-groups


Linear and cyclic oligomers of epichlorohydrin were synthesized and converted by reaction with N-methylimidazole into linear or cyclic derivatives fitted with imidazolium ionic liquid groups. These oligomers containing hydroxyl groups were used as macroinitiators of cationic polymerization of L- and D-lactide. Two types of products were obtained: linear polylactides (PLA's) containing a few ionic liquid groups at the chain end and star PLA's containing a few ionic liquid groups at the core. The enantiomeric forms of PLA, poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA) were used for stereocomplexation studies following earlier observation that if PLLA and PDLA containing one imidazolium ionic liquid group at the chain end are mixed in 1,4-dioxane solution, stereocomplex precipitates spontaneously in form of uniform microspheres. In a present contribution it is shown that if more than one ionic liquid group is introduced at the chain ends of PLLA and PDLA, morphology of precipitated stereocomplex is similar to that observed for PLA's fitted with one ionic liquid group but microspheres are slightly less regular. When few ionic liquid groups are present at the core of star PLLA no specific morphology is observed for precipitating stereocomplex with linear PDLA fitted with C4H9O- group. Only when end-groups able to interacting with each other are introduced, specific morphology appears. With ionic liquid end-groups in linear component, stereocomplex precipitates in form of irregular granules while with strongly interacting ureidopirymidine end-groups, microspheres, although not very regular, are formed. These results indicate that well defined morphology (regular spherical particles) is observed when interacting groups are present at the freely moving chain ends but not, when the same groups are embedded and immobilized at the core of star polymers and through it probably are hidden inside polymer random coil.





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Biedroń, T., Michalski, A., Biela, T., & Kubisa, P. (2021). Stereocomplexation of polylactides containing ionic liquid end-groups. Polimery, 62(4), 254-261.