Synthesis and characterization of poly(epichlorohydrin-B-ethylene glycol) block copolymers by click chemistry method

In this study, synthesis of poly(epichlorohydrin-b-ethylene glycol) block copolymers were carried out by "click" chemistry of terminally propargyl polyepichlorohydrin ester (PECH-propargyl) and terminally azido polyethylene glycol with different molecular weight (PEG-N3). For this purpose, primarily terminally propionyl polyethylene glycols (PEG-Br) were synthesized by the reaction of PEGs (10000 Da, 60000 Da, 4000 Da, 3000 Da, and 2000 Da) and 3-bromopropionyl chloride. Synthesis of PEG-N3 was carried out by means of reaction PEG-Br with sodium azide (NaN3). PECH-propargyl was synthesized by using polyepichlorohydrin and propargyl chloride. Finally, synthesis of poly(epichlorohydrin-b-ethylene glycol) block copolymers were carried out by using PECH-propargyl and PEG-N3. The principal parameters such as concentration, amount of solvent, and polymerization time that affect the reaction were evaluated. The characterization of the products was achieved using nuclear magnetic resonance spectroscopy, Fourier-transform infrared spectroscopy, thermogravimetric analysis, gel-permeation chromatography, and fractional precipitation [non-solvent (petroleum ether-mL)/solvent (THF-mL)] techniques. Keywords: "Click" chemistry, block copolymer, polyepichlorohydrin, polyethylene glycol, fractional precipitation