Shape memory behavior of amorphous polyurethanes

Amorphous polyurethane (PU)-based shape memory polymers (SMPs) were synthesized with different extents of allophanate reactions, hard segment contents, and types of polyol. They were characterized in terms of hydrogen bonding, mechanical, dynamic mechanical, and thermomechanical properties of solution-cast films. Polyols with molecular mass of 500 g/mole resulted in two-phase mixed morphology of the PU. However, the extent of phase mixing depended on the cross-linking density and hard segment content, as well as the type of polyol, and was directly related to the hydrogen bonding determined from the Fourier transform infrared (FTIR) measurements.