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 Tgʹs of PEEUʹs 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 PEUUʹs were high (∼300 °C) for all compositions. The compression sets, tensile sets and hysteresis energy of the PEUUʹs were low and increased with urea content. The use of PPO-co-PEO segments resulted in PEEUʹs with higher compression sets and tensile sets and also more hysteresis. The recovery of the PEUUʹs showed two relaxation regimes: a fast (elastic) recovery and a slower (viscoelastic) recovery. The recovery of these PEUUʹs is almost complete giving time.