Synthesis and characterization poly(ɛ-caprolactone-b- ethylene glycol-b-ɛ-caprolactone) block copolymers by click chemistry method

In this study, synthesis of poly(ԑ-caprolactone-b-ethylene glycol-b-ԑ-caprolactone) block copolymer by "click" chemistry was reported by using propargyl polyethylene glycol (propargyl PEG) and terminally azide poly(ԑ-caprolactone) ester (PCL-N3). For this purpose, primarily propargyl PEG was synthesized by the reaction of PEGs (3000 Da, 2000 Da, 1500 Da, 1000 Da, 600 Da ve 400 Da) and propargyl chloride. 3-azide-1-propanol was obtained by the reaction of 3-chloro-1-propanol and sodium azide. Synthesis of PCL-N3 was carried out by means of ring-opening polymerization of ԑ-caprolactone and 3-azide-1-propanol. Finally, poly(ԑ-caprolactone-b-ethylene glycol-b-ԑ-caprolactone) block copolymers were synthesized by using PCL-N3 and propargyl PEG. The primary parameters such as concentration, time, and temperature that influenced the reactions were assessed. The characterization of the products was achieved using nuclear magnetic resonance spectroscopy, Fourier-transform infrared spectroscopy, gel-permeation chromatography, elemental analysis, and fractional precipitation [solvent (THF-mL)/non-solvent (petroleum ether-mL)] techniques.