Synthesis And Properties Of Blends Of Polyether Polyurethane Elastomers

A blending polyether-based polyurethane elastmer was prepared in this paper. The blending polyethers used were mixtures of polyoxytetramethylene ether glycol (PTMG) and polyoxypropylene ether glycol(TDL/E) with various ratios, of which the TDL/E was a new type product kindly provided by Tianjin's Third Petrochemical Plant. The elastmer was prepared by prepolymer and semi-prepolymer polymerization method respectively. The optimum polymerization processing parameters for each polymerization method were determined, and the two methods were compared in this paper. The influence factors on polymerization rate were discussed, which included the structure of functional group of polyether, the molecular weight of polyether, the content of K+ in the reaction system and so on. Among them, the content of K+ is the greatest effective factor. The results showed that the best way to polymerize the blending polyether-based polyurethane elastmer in the laboratory was by semi-prepolymer polymerization method, adding in the two kinds of polyether at the same time to react in 15 min and controling the content of K"1" in the system.The elastor films were prepared by casting. The effect of various blending ratios on the rheological property of polymer solution was discussed through the test of shear viscosity. The micro-structure and mechanical properties of the elastmer with various blending ratios were examined by means of FTIR, DSC, DMS and tensile test. It was evident that the Tgs of the soft segment decreased, the degree of the microphase separation increased, and the rheological property of the polymer solution improved through mixing proper part of TDL/E into PTMG. The proceeding molding and manufacture of the spandex, therefore became easier. However, as the increasing of the blending ratios, the elastic recovery of elastmers decreased a little.The elastic polyurethane fibers (spandex) were prepared by wet spinning. The effect of various blending ratio on the properties of fibers were tested in this paper. Fibers were treated by heat treatment, and the effect of various heat treatment parameters on fibers were examined. The results showed that the properties of fibers reduced, such as breaking strength, elastic recovery and oxidative degradation stability, but their breaking elongation improved, as the increasing of the blending ratio. The breaking strength and elastic recovery increased by choicing proper heat treatment parameters.