Synthesis and characterization of a novel fluorine-containing triblock copolymer as a potential binder

[Display omitted] •Obtained by the cationic ring-opening polymerization.•The introduction of fluorine-containing units in the HTPE binder.•The fluorine-containing triblock copolymer PFPO-PTMG-PFPO binder has good thermal stability.•The fluorine-containing triblock copolymer PFPO-PTMG-PFPO binder has good application prospect. The polymeric binders play a key role in the solid propellant, so the research on improving the performance of the binder has become particularly important. In this work, a novel fluorine-containing triblock copolymer PFPO-PTMG-PFPO and a fluorine-free triblock copolymer PECH-PTMG-PECH were obtained by the cationic ring-opening polymerization of 2-(2,2,3,3-Tetrafluoro-propoxymethyl)-oxirane (FPO) and epichlorohydrin (ECH) with Polytetramethylene Ether Glycol (PTMG), respectively. In comparison with PECH-PTMG-PECH, the three molecular weights of PFPO-PTMG-PFPO with fluorine-containing side chains had a higher glass transition temperature. With the increase of the fluorine-containing side chains, the molecular weights increased, and the Tg also gradually increased from −64.1 ℃ to −51.8 ℃ in the DSC curves. The TGA-DTG curves indicated that three molecular weights of PFPO-PTMG-PFPO had a good thermal stability, and it was sharp weight loss temperature at around 368.0 ℃. Besides, the viscosity measurement indicated that the viscosity of the higher molecular weight of PFPO-PTMG-PFPO(c) (5357 g/mol) was lower than that of PFPO-PTMG-PFPO(b) (8266 g/mol). When a certain amount of fluorine-containing block was inserted, the influence of low friction coefficient of fluorine-containing polymer was dominant, in which performed the decreased polymer viscosity of the polymer as the increased molecular weight.