Thermal and mechanical properties of multiple-component aliphatic degradable polyurethanes

Macroscopic thermal and mechanical properties of complex aliphatic polycarbonate-based polyurethane (PU) films containing degradable ester units in PU backbone were studied by a combination of several experimental techniques. Differential scanning calorimetry (DSC) revealed that the synthesized oligomeric diol (DL-L) contributes (in addition to polycarbonate diol) to the formation of soft-segment domains, while the hard-segment domains are formed from 1,6-diisocyanatohexane (HDI) and butane-1,4-diol (BD). Three main phase transitions were detected by DSC and by dynamic mechanical thermal analysis. Thermogravimetric analysis (TGA) of two-component PUs showed that the PU made from DL-L and HDI is the least thermostable product, while the PU made from polycarbonate diol and HUT is the most stable one. The differences in the thermal stability of different four-component PUs are not important. Tensile properties very sensitively reflect the changes in composition and in microstructure of PU samples; the best tensile properties exhibits the degradable sample containing the equimolar ratio of hydroxyl groups of macrodiol, oligomeric diol DL-L. and butane-1,4-diol. (C) 2015 Wiley Periodicals, Inc.