Synthesis And Performance Research Of A New Thermoplastic Polyurethane Elastomer

The low molecular weight Polyethylene Oxide (PPG), polyethylene oxide (PECH) and a new type of Epoxy Chloropropane-Tetrahydrofuran Co-polyether were synthesized by cationic ring opening polymerization method wih boron trifluorid-diethyl ether used as catalyst,1,2-dichloroethane served as solvent, ethanediol acted as initiator and several epoxy compounds(such as epoxy propane, epoxy chloropropane and tetrahydrofuran) purposed for monomer. The details of synthetic process could be described as follows:dropping monomer into the mixture solution containing initiator, solvent and catalyst, then controlling the dropping rate carefully at the same time, adding water to terminate the reaction when the reaction had been completed, removing the solvent used by rotary evaporation method to finish the experiment.The synthetic process of hydroxyl-terminated polyethers and co-polyethers had been discussed by the methods of orthogonal test and single-factor experiment. In order to research the optimal conditions of synthetic process, temperature, type of catalyst, dosage of initiator and time for reaction had been discussed as the main factors. The optimal experimental conditions of epoxy chloropropane had been sought out:the dosage of catalyst is6%of the dosage of epoxy chloropropane; the usage of initiator is15%, the reaction time is5hours and gets to an average molecular weight of730. The optimal experimental conditions of polyether epoxy propane had been sought out:the usage of catalyst is1%while initiator is9%of epoxy chloropropane, the reaction time is5hours and gets to an average molecular weight of900.The optimal experimental conditions of hydroxyl-terminated epichlorohydrin-tetrahydrofuran co-polyether had also been sought out:the dosage of catalyst is2.5%and initiator is3.5%of the total mole number of hydroxyl-terminated epoxy chloropropane (ECT) and tetrahydrofuran (THF), the rate of n(THF) and n(ECH) is1.1:1, the reaction time is5hours and gets to an average molecular weight of1090.Series of the hydroxyl-terminated co-polyethers which the molecular weight was around to2000were synthesized by controlling the rate of THF and ECH and the dosage of initintor. Varied types of modified UV curable waterborne polyurethane emulsions were synthesized by using the co-polyethers acted as soft segment, and then did the structure characterization and performance test. The results have been shown that:with the increasing ratio of epoxy chloropropane, the strong polarity halogen atoms in the soft segment increased while the viscosity of emulsions droplet decreased. Besides, the tensile strength of curable film changed from4.6Mpa to6.7Mpa and the elongation at break reduces from162%to113%. When the ratio of THF and ECH grows to1:1, the weightlessness temperature of5%and10%increases from164℃to200℃and220℃to275℃. In addition, the adhesion of the coating significantly increases to1level, also the hardness and impact resistance performance improves.