The Synthesis And Properties Of Fluorinated Polyurethane

The anionic ring-opening polymerization using hexafluoropropylene oxide as raw material in the presence of CsF as catalytic system had been studied. The oligomer of HFPO with acyl fluoride as terminal group had been prepared. The structures of oligomer were fully characterized by IR and NMR spectroscopy.At different temperature, HFPO was catalytically polymerized by CsF in diethylene glycol dimethyl ether (or tetraglycol dimethyl ether) solution. Under these conditions, hexafluoropropylene oxide oligomers with different polymerization degrees were obtained. The influencing factors-reaction temperature, solvent, and the purity of the HFPO were studied. The oligomer with high polymerization degree can be prepared at the temperature of-30℃, using the tetraglycol dimethyl ether as solvent and pure HFPO.Based on the high chemical reaction activity of the group of acyl fluoride, poly-hexafluoropropylene oxide (poly-HFPO) alcohol was prepared by the reduction of the oligomer using LiAlH4. Poly-hexafluoropropylene oxide methyl oxirane was synthesized by poly-hexafluoropropylene oxide (poly-HFPO) alcohol and epichlorohydrin in the presence of tetrabutyl ammonium bromide as a phase transfer catalyst. At last poly-hexafluoropropylene oxide-1,2-diol was prepared by poly-hexafluoropropylene oxide-methyl-oxirane and perchloric acid. The structure of the fluorochemicals were confirmed by means of IR spectroscopy,19F NMR spectroscopy and1H NMR spectroscopy.Ethylene glycol monododecafluorineheptyl ether methyl oxirane was synthesized by ethylene glycol monododecafluorineheptyl ether and epichlorohydrin in the presence of tetrabutyl ammonium bromide as a phase transfer catalyst. Then ethylene glycol monododecafluorineheptyl ether-1,2-diol was prepared by ethylene glycol monododecafluorineheptyl ether methyl oxirane and perchloric acid. The structure of the fluorochemicals were confirmed by means of IR spectroscopy,19F NMR spectroscopy and1H NMR spectroscopy.Fluorinated polymers exhibit many interesting properties due to the unique characteristics of the fluorocarbon chains. Fluorinated polyurethanes (FPU1, FPU2) were prepared based on hydroxyl-terminated polybutadiene (HTPB) as main chain, toluene diisocyanate and chain extended with ethylene glycol monododecafluorineheptyl ether-1,2-diol and poly-hexafluoropropylene oxide-1,2-diol. At the same time, polyurethane of HTPB-BDO was prepared by using1,4-butanediol as chain extender. Their structures were characterized by IR techniques.The contact angle, tensile strength and and thermal property of the polyurethanes were measured. The results showed that the low surface energy of fluorinated segments resulted in the water contact angle of the fluorinated polyurethanes films increased and the hydrophobicity of the film increased. The thermostability and tensile strength of the fluorinated polyurethanes also increased because of the addition of fluorine atom in the polyurethane.