Flexible polyurethane-based phase change composites with ultra-fast curing and thermal management capabilities

Phase change material (PCM) have several drawbacks, including liquid leakage, solid brittleness, low thermal conductivity and monofunctionality. In order to address these shortcomings, this study used polyurethane (PU) as the flexible packaging materials, palmitic acid (PA) as the phase change material, and h-BN as a thermal conductivity enhancer to create BN/PUPCM composite films with spatial network structure using prepolymerization crosslinking and physical mixing. The latent heat and thermal conductivity of the films can be efficiently enhanced by the PA and h-BN dispersed throughout the matrix structure. The composite film with R value of 1.5 and PCM content of 30% has a good heat storage capacity, and its latent heat can reach 102.28 J/g. The BN/PUPCM@30 composite film exhibited a good mechanical performance, achieving a tensile strength of 12.0 MPa coupled with exceptional ductility (457.0% elongation at break). The energy storage capacity of BN/PUPCM@30 remained constant even after 100 heating/cooling cycles, suggesting reversible energy storage capability and long-term thermal dependability. Furthermore, the BN/PUPCM@30 composite film displayed ultra-fast curing properties, achieving complete film formation within 4 min at 90 °C. Furthermore, introducing h-BN significantly improves the photothermal conversion and absorption of PUPCM, raising the temperature of the composite film by 4.9 °C, as can be seen from the infrared thermography. During the cooling process, an excellent temperature control capability was demonstrated by a constant temperature plateau lasting approximately 300 seconds. This work offers a novel method for creating polyurethane-based composite PCM with ultra-fast curing and thermal management capabilities.