Improvement of acid modification and its effect on the adsorption of stearic acid into sepiolite

To improve sepiolite's ability to absorb stearic acid, different hydrochloric acid modification conditions were used to modify sepiolite. Stearic acid was encapsulated by direct dipping modified sepiolite. The leakage test was carried out. The crystal structure, microstructure, latent heat, thermal stability and thermal conductivity were characterized. The improved acidification condition of 4 mol L−1 for hydrochloric acid concentration, 6 h for acidification time and 313.15 K for acidification temperature can improve the load rate of stearic acid for 5 mass% relative to previous experimental data, the load mass fraction of stearic acid can reach to 40%. The composite prepared by improving acidification conditions has higher latent heat of melting and solidification of 74.66 J g−1 at 346.65 K and 77.02 J g−1 at 332.05 K, respectively. The composite phase change materials prepared by physical stirring have good chemical compatibility and thermal durability.