Open Access

ARTICLE

Synthesis, Characterization, and Micellization Behavior of Poly(L-lactide) and Poly(ethylene glycol) Block Copolymers in the presence of a Novel Organocatalyst

by

a School of Chemistry & Material Science, Shanxi Normal University, Linfen 041004, P.R. China
b Collaborative Innovation Center for Shanxi Advanced Permanent Magnetic Materials and Technology, Linfen 041004, P.R. China

* Corresponding Author: e-mail:

Journal of Polymer Materials 2018, 35(4), 393-408. https://doi.org/10.32381/JPM.2018.35.04.1

Abstract

Biodegradable poly(L-lactide)-poly(ethyleneglycol)-poly(L-lactide) (PLLA-b-PEG-b-PLLA) triblock copolymers and 4-arm star-shaped poly(ethylene glycol)-poly(L-lactide) (4-arm star-shaped PEGb-PLLA) block copolymers were synthesized via ring-opening polymerization of L-lactide (LLA) in the presence of hydroxyl-terminated α, ω-dihydroxy PEG2000 (PEG2000) and 4-arm PEG as a macroinitiator and 2, 3, 6, 7-tetrahydro-5H-thiazolo [3, 2-a] pyrimidine (ITU) as an organic catalyst. The resultant copolymers were analyzed using various techniques including 1 H NMR, FTIR, GPC and DSC. The micellar aggregates were formed from the amphiphilic block copolymers. The relationship between the architecture of block copolymers and their micellization properties, such as critical micelle concentration (CMC) and size of micelles, was investigated. The CMC and micelle size were measured by the steady-state pyrene method and dynamic light scattering, and the results indicated that the formation of micelles became easier for 4-arm star-shaped PEG-b-PLLA copolymer as compared with PLLA-b-PEG-b-PLLA copolymer. The TEM micrographs confirmed the PLLA-core/PEG-shell structure of the micelles.

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Keywords

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