Elastic behavior of flexible polyether(urethane–urea) foam materials

Polyether(urethane–urea) foams (PEUU) with varying urea contents and different polyether segments (PPO and PPO-co-PEO (93/7 w/w)) were compacted to transparent solid plaques via compression molding. The thermal, mechanical and elastic properties of the compacted PEUU materials were studied. With increasing urea content, the shear modulus was increased, while the glass transition temperature (Tg) remained low and unaffected. The Tg's of PEEU's with PPO segments were, however, lower than with PPO-co-PEO segments, indicating more mixing of urea segments with PPO-co-PEO. The flow temperatures of both PEUU's were high (300 °C) for all compositions. The compression sets, tensile sets and hysteresis energy of the PEUU's were low and increased with urea content. The use of PPO-co-PEO segments resulted in PEEU's with higher compression sets and tensile sets and also more hysteresis. The recovery of the PEUU's showed two relaxation regimes: a fast (elastic) recovery and a slower (viscoelastic) recovery. The recovery of these PEUU's is almost complete giving time.