Preparation and characterization of polyurethane foams containing microencapsulated phase change materials for thermal energy storage and thermal regulation

Polyurethane (PU) foam is widely used as a thermal insulating material but it does not possess thermal energy storage and thermal regulation properties. In the present work, the phase change material stearic acid (SA) is microencapsulated with melamine‐formaldehyde resin and then introduced into PU prepolymer to fabricate composite foams. In this way, the phase change properties of SA are successfully infused into the PU foams, leading to improved heat storage and thermal regulation ability. The phase change enthalpy of composite PU foams can be facilely tailored from 3.45 to 14.59 J g −1 by changing the loading fraction of microcapsules, allowing an adjustable thermal energy storage and thermal regulation capacity. The composite PU foams exhibit good thermal reliability after 100 cycles of thermal testing. Morphology observation confirms strut rupture and broken cells as well as the distribution of the incorporated microcapsules inside the cell struts. It is found that the added microcapsules have a small influence on the foam density and thermal conductivity. Finally, the microcapsules present a marked effect on the mechanical properties, with an increased elastic modulus from 3.52 to 4.21 MPa and decreased compression strength from 0.29 to 0.13 MPa. We believe that our efforts on the design and development of composite PU foams with thermal energy storage and thermal regulation properties will contribute to broaden the application scope of PU foams. © 2020 Society of Industrial Chemistry