Fabrication of Low‐Density Ethylene−Vinyl Acetate/Olefin Block Copolymer Foam with Well Rebound Properties Blown with Mixed N₂/CO₂

Thermoplastic elastomer foams, such as ethylene−vinyl acetate (EVA) foams, have received extensive attention for their soft touching, low‐density, and excellent mechanical properties and have been emerging in lightweight footwear. However, the EVA foam suffers from its inadequate rebound resilience properties and poor thermal stability due to the low melting point. Herein, olefin block copolymer (OBC) with excellent rebound properties and high melting peak temperature of 120 °C is introduced into the EVA matrix to improve its foaming behavior and foam properties. A series of lightweight EVA/OBC composite foams with adjustable cellular structures are prepared by supercritical mixed N 2 /CO 2 . It is worth noting that the foaming temperature windows are greatly improved under the action of OBC, and an extremely low‐density as low as 0.06 g cm −3 is achieved. In addition, the as‐prepared EVA/OBC foams exhibit the improved foam shrinkage resistance, resulting from the rapid crystallization ability of OBC phase. Furthermore, the residual strain and hysteresis loss ratio of as‐prepared elastomer foams are as low as 1.56 and 12.95%, respectively. These distinct advantages together with the green foaming process make the EVA/OBC elastomer foams very promising toward high‐performance flexible cellular polymeric materials.