Design of core-shell chitosan-based phase change microcapsules towards improving the thermal management capability and fire safety of polyurethane

The flammability properties of rigid polyurethane foam (RPUF) and phase change materials (PCMs) limit its applicability. This research employed organic montmorillonite (OMMT) and chitosan (CS) as shell materials, with paraffin serving as the core material, to effectively produce innovative OMMT CS phase change microcapsules (OMMT/CS/PCM). The integration of OMMT/CS/PCM into RPUF markedly improved the flame-retardant characteristics of the polyurethane. The performance was extensively assessed using differential scanning calorimetry (DSC) and cone calorimetry. Experimental data reveal that at a content of 30 wt% OMMT/CS/PCM, the phase change latent heat of RPUF-30% OMMT/CS/PCM is 7.514 J g -1 , the limiting oxygen index (LOI) is 32.4%, and the flame retardancy index (FRI) varies from 1 to 20, indicating superior flame-retardant characteristics and a significant reduction in fire risk. OMMT and CS establish a barrier effect that is essential in reducing the diffusion of flammable gases and impeding heat transfer, thereby markedly enhancing the flame-retardant characteristics of the composite material. This work offers novel insights into the utilization of PCMs in RPUF.