Resistance to High Temperature
Melting of the hard segment will cause failure in the elastomer
Urea hard segments typically melt 50oC (90oF) higher than urethanes formed by diol cures
Isocyanate PPDI (DuPont) enhances resistance to high temperature
At temperatures lower than the melting point, the soft segment has more effect on the properties
Polyester soft segments permit better retention of physical properties and are resistant to oxidation