Low‐Loading Silane‐Modified SiO ₂ ‐Reinforced MOCA ‐Based Cast Polyurethane Elastomers: Enhanced Wear Resistance and Mechanical Performance

ABSTRACT 4,4′‐Diaminodiphenylmethane (MOCA)‐based cast polyurethane (CPU) elastomers possess excellent mechanical properties but often exhibit insufficient wear resistance under high‐load or abrasive conditions. To address this, surface‐modified silica nanoparticles (D‐SiO 2 ) were prepared using (N, N‐dimethyl‐3‐aminopropyl)trimethoxysilane (DAPS) and incorporated into the CPU matrix via a solvent‐assisted casting method. The introduced tertiary amine and organic groups on D‐SiO 2 facilitated covalent bonding and hydrogen bonding with the CPU, significantly enhancing interfacial compatibility and dispersion uniformity. At an optimal loading of 0.3 wt%, the composite achieved a remarkable tensile strength of 59.1 MPa and an elongation at break of 394.75%, representing a substantial improvement over the neat CPU (44.2 MPa, 376.33%). Furthermore, the wear resistance was notably enhanced, with the abrasion volume reduced by 34% compared to the unfilled system, while the friction coefficient remained stable. This work demonstrates that low‐loading, surface‐modified silica can effectively reinforce MOCA‐based CPUs, offering a viable strategy for developing high‐performance MOCA‐based CPU elastomers.