Lightweight olefin block copolymers foams with shrinkable and recoverable performance via supercritical CO₂ foaming

Thermoplastic elastomer foams with gas-rich structures occupy a high specific surface/volume ratio, which will take up lots of space for storage and transportation. Herein, micro-crosslinked olefin block copolymers (OBC) foams with shrinkable and recoverable functions were prepared via supercritical CO₂ foaming to subtly solve the storage problem, and the shrinkage and recovery mechanisms were studied. The storage volume of OBC foams could shrink up to ∼78.5 % and maintain low volume condition for a long time through vacuum sealing technology. Meanwhile, the shrunk OBC foams could also be quickly and fully recovered by N₂-assisted post-processing because of the regulation of gas exchange. And OBC foams with a density of 0.028 g/cm³ were prepared successfully. The compressive properties of OBC foams were investigated. Related design strategies can significantly reduce the transportation costs and energy consumption of OBC foams and are expected to be applied to other thermoplastic elastomers.