Metal foam

Materials science

Layer (electronics)

Thermal conductivity

Molding (decorative)

Mold

Porosity

Thermal insulation

Physics

Compression molding

Soundproofing

Thermal

Composite material

Polyurethane

Meteorology

Syntactic foam

Blow molding

Blowing agent

European Polymer Journal

Polyether block amide (PEBA) is a thermoplastic elastomer that offers a unique combination of low density, flexibility, small hysteresis and excellent flex fatigue resistance. Foaming is an effective method to save material, reduce weight, and tune mechanical properties, and thus to broaden the applications of PEBA. Here we report a flexible and scalable strategy to fabricate low-density PEBA foams via mold-opening foam injection molding. PEBA foams with tunable cellular structure were fabricated. The lightweight PEBA foam with a density of 0.17 g/cm3 exhibits super elasticity with an energy loss coefficient less than 25%, a resilience value up to 82%, and a compression set less than 5%. Moreover, it also performs outstanding while anisotropic thermal insulation properties, with an in-plane thermal conductivity of 30 mW·m−1·K−1 and a through-plane thermal conductivity of 50 mW·m−1·K−1. Furthermore, the lightweight PEBA foam also presents excellent acoustic insulation properties in a wide frequency range from 1000 Hz to 4000 Hz. Interestingly, it is found that smaller cell size contributes to enhanced strength, elasticity, and sound insulation. The lightweight, super-elastic, and thermal-sound insulation bio-based PEBA foams with tunable structure show a promising future in many applications such as sportswear, protective materials, and insulation materials.

Lightweight, super-elastic, and thermal-sound insulation bio-based PEBA foams fabricated by high-pressure foam injection molding with mold-opening