Synthesis and characterization of novel ABA type poly(Ester-ether) triblock copolymers

ATAKAY, MEHMET/0000-0002-7102-2974WOS: 000466029400003Oligomers of poly(3-hydroxypropionate) (P3HP) were synthesized via hydrogen transfer polymerization of acrylic acid. Olefinic end-group of the oligomers were modified through epoxidation and bromination to obtain activated oligomers with epoxy and bromide end-groups, respectively. Terminally hydroxyl oligomeric poly(ethylene glycol) (PEG-1450) was also converted to sodium alkoxide of PEG-1450 through reaction with sodium hydride. Novel ABA type P3HP-b-PEG-b-P3HP triblock copolymers were successfully obtained through simple nucleophilic addition reactions between alkoxy and epoxy/alkyl bromide. Water uptake measurements of the triblock copolymers were calculated. Characterization of the modified oligomers and the triblock copolymers was performed by using FT-IR, H-1-NMR and MALDI-MS analyses. Thermal transitions and degradation features of the copolymers were investigated by using DSC and TGA methods. Spectroscopic and thermal analyses revealed that both end-group modifications and coupling reactions were successfully achieved.Ordu University Scientific Research Fund [ODU-BAP HD-1606]This work was supported by Ordu University Scientific Research Fund (grand number: ODU-BAP HD-1606)

Synthesis and characterization of the ABA-type poly(ester-ether-ester) block copolymers

WOS: 000523671800001Polyethylene glycol with average molar mass of 1,450 Da (PEG-1450) was treated with equivalent amount of sodium hydride to convert hydroxy groups to sodium alkoxide. Assuming the PEG oligomer with alkoxy end-groups as a macroinitiator, anionic ring-opening polymerization of some lactones (beta-propiolactone, alpha-methyl-beta-propiolactone, delta-valerolactone and epsilon-caprolactone) with different ring sizes were performed to obtain the ABA-type poly(ester-ether-ester) block copolymers. Copolymers with various compositions were obtained with high yields. Spectroscopic and thermal characterization of the copolymers were performed by using DSC, TGA, FT-IR, and H-1-NMR spectroscopy. Formation of the block copolymers and their mass distributions were determined by MALDI mass spectrometry. Structural analyses of the copolymers revealed that chain extensions increased in order of alpha-methyl-beta-propiolactone, beta-propiolactone, delta-valerolactone and epsilon-caprolactone