Thermal Property Enhancement of Paraffin-Wax-Based Hydroxyl-Terminated Polybutadiene Binder with a Novel NanoSiO₂-Expanded Graphite-PW Ternary Form-Stable Phase Change Material

Abstract

High volume change and low thermal conductivity will impede the application of paraffin wax (PW). Expanded graphite (EG) is one of the best materials to shape-stabilize PW and improve its thermal conductivity. NanoSiO2 is also considered as a good supporting material of PW. Herein, a novel nanoSiO2-EG-PW ternary form-stable phase change material (FSPCM) with enhanced thermal properties was reported. Subsequently, the effect of nanoSiO2-EG-PW with different amounts on the chemical composition, morphology, and thermal properties of PW-based hydroxyl-terminated polybutadiene (HTPB) was investigated using Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermal gravimetric analyzer (TGA), thermal cycling test, and thermal conductivity, respectively. These results indicated that nanoSiO2-EG-PW could effectively shape-stabilize PW in the HTPB matrix without chemical reaction. The thermal conductivity of nanoSiO2-EG-PW was improved from 0.303 W·m–1·K–1 to 0.602 W·m–1·K–1, compared with that of PW. The nanoSiO2-EG-PW/PW/HTPB composites kept high latent heat capacity, delayed melting temperature, and good thermal reliability after 500-thermal-cycling. Moreover, the thermal stability and thermal conductivity of the composites increased, with the increasing content of nanoSiO2-EG-PW. Therefore, these materials have a potential application in high-temperature phase change material (PCM) and HTPB binder.