Development of Poplar Wood/Bio-Based Composite Phase-Change Material as Novel Ecofriendly Thermo-Regulative Material

This study examined the enhancement of thermal properties in wood through impregnation with tallow (TW) and myristic acid (MA) to create a bio-based phase-change material (BPCM) suitable for energy-storing interior building materials. Poplar sapwood was impregnated with TW/MA mixtures in ratios of 30:70, 50:50, and 70:30. Leakage tests revealed a maximum leakage of 2.8% for the 30:70 ratio at 70 °C for 20 min. The weight percentage gain (WPG) reached 112.0%. Fourier transform infrared spectroscopy (FTIR) confirmed the physical combination of the TW/MA mixture and poplar wood. The mixture exhibited a phase-change temperature of 50.5 °C and latent heat of 172 J/g. The differential scanning calorimetry (DSC) results showed a latent heat capacity of 73.6 J/g and a melting temperature of 45.9 °C for the ratio of 50:50. Thermoregulation tests demonstrated an indoor temperature that was sustained within tolerable ranges and reduced room temperature fluctuation. Thermal conductivity decreased by 41.4% in tallow impregnated samples but increased by 10% in the TW/MA mixture. Wood samples impregnated with phase-change materials exhibited 90.71% fungal resistance. Overall, BPCMW showed promise for the practical storage and release of solar thermal energy, with tallow-impregnated wood (TW-W) displaying a superior performance, offering significant benefits in reducing building heating and cooling loads.