Controllable Synthesis Of Fluorinated Polyurethane Cationic Polymerization Technology And Performance Characterization

Cationic polymerization was adopted to prepare fluorinated polyglycol （FPO）with controllable molecular weight. The chain structure and sequence of FPO weredetailedly analyzed by¹H-NMR and¹³C-NMR and then PFO was used as precursorsto make fluorinated polyurethane （FPU）.Firstly, fluorine containing epoxy （FO） compound was one-step synthesizedfrom2,2,3,3-Tetrafluoro-1-propanol （TFP） and epichlorohydrin （ECH） using liquidalkali solution as catalyst. The influence of reaction time and the alkali types on theyield of FO were investigated. The results show that KOH solution promotes thehydrolysis reaction leads to lower yield compared to NaOH solution due to itsstronger alkaline. Meanwhile, increasing reaction time results in lower yield sincewater byproduct stays in reactor and thereby extends the hydrolysis reaction.Secondly, the fluorinated glycol （FPO） was synthesized using tetrahydrofuran（THF） and the FO as the monomers. The Kelen-Tudos model was used to calculatethe reactivity ratio of monomers and choose the feeding way of adding activemonomer. The ratio of FO and THF was optimized to prepare FPO. On the basis oftheory of controllable cationic polymerization, the influence of nucleophilic reagentand non-ploarity solvent on the stability of cations, and the relationship betweentheoretical molecular weight and real molecular weight of FPO, were systemicallydiscussed. In order to control the sequence of FO and THF, the chain structure ofFPO was fully characterized by¹H-NMR and¹³C-NMR.Finally, FPU was synthesized using FPO and methyl diphenylenediisocyanate （MDI） as soft and hard segments, respectively. X-ray photoelectronspectroscopy （XPS） and tensile test machine were applied to investigate the fluorinecontent and adhesive force of surface of FPU.