Flexible biomass-based phase change materials: L-N-Ti for environmentally friendly thermal management

Traditional phase change materials (PCMs) offer broad application potential but face challenges such as environmental unfriendliness, high rigidity and poor heat transfer performance, resulting in low utilization efficiency. In this study, using biomass loofah sponge (LS) as the main framework and natural rubber latex (NRL) as the flexible modifier, the biomass-based PCMs (L-N) were successfully synthesized after encapsulating lauric acid (LA). The addition of nano-TiO₂ further enhanced thermal conductivity, ultimately leading to the development of flexible composite PCMs, L-N-Ti. In-depth characterizations revealed that the introduction of NRL significantly improved the system's strength and toughness, with tensile strength peaking at 1.161 MPa at 19.2 % NRL content, while maximum elongation at break reached 38.65 % at 26.3 % NRL. The incorporation of 7.4 wt% TiO₂ significantly boosted thermal conductivity to 0.57 W/(m·K), a 185 % increase over the unmodified material. Simultaneously, the energy storage efficiency (E_m) of L-N-Ti consistently exceeded 89.89 %, with only a 9.34 % loss in latent heat of fusion after 100 thermal cycles, indicating robust thermal stability. The successful advancement of L-N-Ti not only addresses the mechanical constraints inherent but also offers a sustainable biomass-based solution for effective thermal management within the 20°C–60 °C range.