High thermal storage polyurethane composite embedded with microencapsulated phase change materials and analysis of its unsteady heat transfer

Form-stable composite phase change materials exhibit considerable application prospects in the insulation of submarine oil and gas pipelines due to their good chemical stabilities, levels of thermal insulation, and leakage resistances. In this study, composite phase change materials (PU-MPCM) were prepared for application in submarine oil and gas pipelines using a polyurethane (PU) matrix and different contents of a microencapsulated phase change material (MPCM). The unsteady heat transfer of PU-MPCM was studied using the COMSOL Multiphysics modeling software, and an insulation study was conducted using the composites. PU-MPCM exhibited a high thermal storage performance and favorable shape stability, and the relative effective enthalpy coefficients of PU-MPCM with different MPCM contents were greater than 80%. The maximum amount of added MPCM was 24 wt% (PU-MPCM24), and the melting enthalpy of PU-MPCM24 reached 35.95 kJ/kg, with an effective thermal conductivity as low as 0.16 W/(m K). The holding time of PU-MPCM24 could be increased by 229.79% compared to that of pure PU, and PU-MPCM exhibited good mechanical properties and low water absorption, rendering it suitable for use in underwater environments. These excellent thermal properties indicate the considerable potential of PU-MPCM24 for use in the thermal management and insulation of submarine oil and gas pipelines. Polyurethane composite embedded with microencapsulated phase change materials shows excellent thermal storage performance and good adaptability to underwater environments.