Influence of the hard segment contents on mechanical behavior of some poly(ether-urethane-urea)s

In this study, a series of three different thermoplastic poly(ether-urethane-urea)s were synthesized from hexamethylene diisocyanate (HDI), polypropylene glycol (PPG) as macrodiols and hexamethylene diamine (HMDA) as chain extender The molecular weights of the macrodiols were in the range 400 2000 g/mol. The polymers have been characterized by means of H-1-NMR, IR spectroscopy and other techniques. Tensile testing was performed on dumbbell-shaped specimens cut from thin films at room temperature on a TIRAtest 2161 tensile tester (Germany). The hard segment contents were calculated on the basis of urea content, as described by Flory, which represents the best method of the evaluation of the material residing in the hard phases.