Amino-Functionalized Single-Walled Carbon Nanotubes-Integrated Polyurethane Phase Change Composites with Superior Photothermal Conversion Efficiency and Thermal Conductivity

The development of organic phase change materials (PCMs) with good shape stability, superior photothermal conversion efficiency, and high thermal conductivity is critical for practical photothermal utilizations. Herein, novel form-stable solar-thermal conversion and storage materials (SPCMs) with superior photothermal conversion efficiency and thermal conductivity were successfully synthesized by introducing amino-functionalized single-walled carbon nanotubes (SWNTs–NH₂) into poly­(ethylene glycol)-based polyurethane PCM. Differential scanning calorimetry (DSC) and thermal conductivity test results showed the SPCMs possessed relatively high phase change enthalpies in the range of 124.0–126.1 J/g and that the introduction of SWNTs–NH₂ effectively enhanced the thermal conductivities of SPCMs. Sunlight irradiation experiments showed that the introduction of SWNTs–NH₂ into PEG-based polyurethane PCM significantly improved the solar-thermal conversion and storage efficiency of SPCMs from 44.8% to 89.3%. The light irradiation cycling tests and thermogravimetric (TG) analyses indicated that the SPCMs exhibit satisfactory reversible stability and thermal stability. Moreover, SPCMs with SWNTs–NH₂ added exhibited much higher solar-thermal conversion and storage efficiency and better reversible stability than SPCM with SWNTs added. In conclusion, the synthesized SPCMs show considerable potential for solar-thermal conversion and storage applications.