Towards novel functional polymers: Ring-opening polymerization of L-lactide with p-tert-butylthiacalix[4]arene derivatives

Abstract

© 2020 Elsevier B.V. Oligo−/polylactides functionalized with p-tert-butylthiacalix[4]arenes in three conformations (cone, partial cone, 1,3-alternate) were synthesized by ring-opening polymerization. Conformational isomers of p-tert-butylthiacalix[4]arene tetrapropanolamide derivatives differing in relative position of hydroxyl groups were introduced into reaction with L-lactide in presence of catalytic amounts of tin (II) octoate in DMSO and 1,2-dimethylbenzene. It was shown that oligo−/polyester molecular weight depends on macrocycle's conformation and solvent used for L-lactide ROP. Highest molecular weight was achieved for 1,3-alternate conformation and 1,2-dimethylbenzene, while on the contrary in DMSO higher molecular weight was achieved for cone stereoisomer. Regardless molecular weight of oligo−/polylactides synthesized, 1,3-alternate stereoisomer derivatives are characterized by higher thermal stability, indicating that the relative position of oligo−/polylactides fragments, which are pre-oriented by cyclophane core is the key factor determining thermal stability of oligo−/polylactides synthesized. Modification of polyesters with thiacalixarene fragment bestows them with sorption activity towards rhodamine 6G in contrast to non-modified polylactide.