Dual‐Enhancement of Macro/Microstructures in Polyurethane Foam: Synergistic Effect of Biomimetic Silicone Skeleton and Hollow Glass Microspheres

The low strength and stiffness of polyurethane foam (PUF) restrict its application in advanced energy‐absorbing structures. Here, we develop a biomimetic hollow glass microsphere (HGM)‐filled polyurethane foam (PUFH) composite reinforced with a gradient‐tapered tubular spider‐web silicone skeleton. The silicone architecture enhances load transfer and structural support, while HGM incorporation modifies the cellular structure and strengthens the foam matrix. Among the investigated configurations and HGM loadings, Tts‐web/PUFH containing 50 wt.% HGM exhibited the best overall mechanical performance, with an elastic modulus, compressive strength, and specific energy absorption approximately 40, 16, and 3 times those of pristine PUF, respectively. Moreover, the unfilled silicone skeleton retained more than 90% of its initial specific energy absorption after three compression cycles, indicating good recoverability. The enhanced mechanical response is attributed to the combined effects of macroscale stress redistribution by the biomimetic skeleton and microscale cellular refinement associated with HGM incorporation. These results demonstrate a dual‐scale reinforcement strategy for developing lightweight PUF‐based composites for cushioning and impact‐protection applications.