||In this study, boron-doped carbon nanotubes were synthesized by high-temperature heat treatment with a boric acid precursor and single-walled carbon nanotubes instead of the conventional chemical doping process. Then, these boron-doped single-walled carbon nanotubes were added to polyurethane to prepare polyurethane nanocomposites having excellent thermal and mechanical properties. Changes in properties that occurred due to structural changes inside the composite were investigated as the added amount of nanofiller was increased. In particular, a near-infrared laser (808 nm) was directly irradiated on the nanocomposite film to induce photothermal properties generated by a local surface plasmon resonance effect on the surface of the CNTs. The newly developed material can be applied to electronic devices and products as a heat-generating coating material, de-icing of airplane, etc., using a moulding process.