Effect of Graphene Dispersion Controlled by Solid‐State Shear Milling on the Mechanical Properties of Polyoxymethylene/Polyurethane/Graphene Multiphase Composites

ABSTRACT Polyoxymethylene (POM), renowned for its exceptional mechanical strength, electrical insulation, and chemical resistance, faces critical limitations in engineering applications due to inherent brittleness caused by high crystallinity. To address this challenge, we propose a groundbreaking approach using solid‐state shear milling (S 3 M) technology to fabricate a ternary POM/thermoplastic polyurethane (TPU)/graphene composite with a unique core‐shell architecture. Unlike conventional methods requiring solvents or chemical functionalization, S 3 M enables solvent‐free, energy‐efficient exfoliation and homogeneous dispersion of graphene within the POM‐TPU matrix. By precisely tailoring the multiphase domain structure, the optimized composite achieves a tensile strength of 52.3 MPa, marking an 11.0% enhancement over the baseline, and an impact strength of 11.6 kJ/m 2 , demonstrating a 33.3% improvement—all at a minimal graphene loading of 0.1 wt%. These results surpass the performance of traditional TPU‐toughened POM and rival nanocomposites such as POM/carbon nanotube systems. This innovation not only overcomes the long‐standing trade‐off between toughness and stiffness in POM‐based materials but also offers a scalable, eco‐friendly solution for high‐performance engineering plastics, with direct implications for automotive, aerospace, and wearable electronics industries.