Enhanced the Ablation Resistance of Sprayable Polyurethane Elastomer Composites by Adding TiB2 and SiCw

Sprayable polyurethane elastomers integrate outstanding mechanical properties with excellent adhesion, enabling firm bonding to diverse materials such as metals. However, their inadequate high-temperature resistance and inherent flammability restrict their application in extreme environments. This study incorporated silica (SiO2) and montmorillonite (MMT) to optimize the compatibility between inorganic ceramic particles and the polymer matrix. Titanium boride (TiB2) and silicon carbide whiskers (SiCw) were employed as ceramicized fillers, with aramid pulp added as a dispersion-strengthening phase, successfully developing a ceramicizable polyurethane-based thermal insulation material. The results demonstrated that when both TiB2 and SiCw were added at 1.2 g, the composite achieved optimal comprehensive performance: tensile strength increased from 5.14 MPa to 6.34 MPa, mass retention at 1000 °C reached 30.50%, and after oxygen-acetylene ablation testing, the linear ablation rate was 0.180 mm/s with a mass ablation rate of 0.0706 g/s. Multiple characterization revealed that graphitic carbon derived from polyurethane pyrolysis, molten SiO2 at elevated temperatures, and oxidation decomposition products of TiB2 (such as TiO2 and B2O3) collectively formed a multi-phase ceramic-glass composite. This composite effectively fills voids generated in the material under high-temperature conditions, densifies the carbon layer structure, and significantly enhances the ablation resistance of polyurethane elastomer thermal insulation materials.