Journal of Applied Polymer Science, Vol.71, No.1, 83-91, 1999
Segmented and nonsegmented polyurethanes : Polyaddition products of 4,4 '-bis(2-hydroxyethoxy)diphenyl ether and 1,6-hexanediisocyanate
New linear polyurethanes (PUs) derived from 4,4'-bis(2-hydroxyethoxy)diphenyl ether (4-HEDE) and 1,6-hexanediisocyanate (HDI) were synthesized by either melt or solution polymerization. We found that the properties of PUs obtained are dependent mainly on the kind of organic solvent, contribution of the catalyst, and concentration of the monomers used. Good results are obtained using aprotic solvent-N,N-dimethylformamide, similar to 30 wt % concentration of monomers, dibutyltin dilaurate as a catalyst, and conducting the process at 90-100 degrees C for 4 h. This article presents basic properties of the series of PUs obtained. Thermal properties of the polymers were investigated by means of thermal gravimetric analysis and differential scanning calorimetry. Molecular weight distribution was determined by gel permeation chromatography. Shore hardness and tensile test results are also presented. The structure of the resulting products was confirmed by elemental analysis, Fourier transform infrared spectroscopy and X-ray diffractometry. We also present the properties of copolyurethanes type 4-HEDE/HDI/1,6-hexanediol or 4-HEDE/HDI/polytetramethylene oxide containing variable amounts of 1,6-hexanediol or polytetramethylene oxide ((M) over bar(n) similar to 650) synthesized in the optimal conditions established earlier for PU 4-HEDE/HDI.
Keywords:LIQUID-CRYSTALLINE POLYURETHANES, ISOMERIC PHTHALOYL CHLORIDES;ALIPHATIC ACID DICHLORIDES, INTERFACIAL POLYCONDENSATION;LINEAR POLYTHIOESTERS, BIS(4-HYDROXYPHENYL)ETHER, POLYESTERS