A Strategic Approach to Improving Interfacial Interactions in <scp>TPU/POSS</scp> Composites via Ball Milling of <scp>POSS</scp>

ABSTRACT We synthesized TPU/POSS composites through a two‐step process involving the ball milling of POSS to reduce its particle size, followed by in situ polymerization of TPU to reinforce the material. The reduction of POSS particle size via ball milling enhanced the dispersion of POSS in the TPU matrix, leading to stronger interfacial interactions between the TPU chains and POSS surfaces. This approach significantly improved the thermomechanical performance of the TPU/POSS composites compared to neat TPU. Specifically, the incorporation of ball‐milled POSS resulted in a ~28%, ~20%, and ~27% enhancement in tensile strength, elongation at break, and 100% modulus, respectively, even with an ultra‐low loading of 0.5 wt% POSS. Moreover, the viscoelastic properties of the composites showed remarkable improvements, especially at elevated temperatures (130°C–170°C). The storage modulus at 130°C increased by ~24%, the maximum application temperature rose by 6°C, and the creep modulus improved by ~40%, confirming the material's suitability for demanding applications. This study demonstrates that ball milling of POSS followed by in situ polymerization of TPU is an effective strategy for developing high‐performance TPU/POSS composites with enhanced mechanical and viscoelastic properties.