On the mechanocaloric effect of natural graphite/thermoplastic polyurethane composites

• Published in: Journal of materials science 2023-07, Vol.58 (27), p.11029-11043
• Main Authors: Colman, Flávio Clareth, da Silva, Nicholas Dicati Pereira, Imamura, William, Usuda, Erik Oda, Moro, Fernando Rodrigo, Carvalho, Alexandre Magnus Gomes, Alves, Cleber Santiago, Trevizoli, Paulo Vinícius, de Cássia Colman Simões, Rita, de Oliveira, Júlio César Dainezi, Favaro, Silvia Luciana, Bocca, Jean Rodrigo, Radovanovic, Eduardo
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; Composite materials; Composites & Nanocomposites; cooling; Crystallography and Scattering Methods; Elastomers; Electric properties; entropy; graphene; Graphite; Heat conductivity; Heat transfer; Materials Science; Mechanical properties; Polymer Sciences; Polyurethane resins; Polyurethanes; Reduction; refrigeration; Refrigeration equipment; Solid Mechanics; Solid state; temperature; Thermal conductivity; Thermodynamic properties; thermoplastics; Urethane thermoplastic elastomers; Vapor compression refrigeration
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-023-08700-3

Solid-state cooling based on caloric effects is an alternative to traditional vapor-compression refrigeration systems. This technique and the solid-state materials have received great attention in recent decades. For example, the elastomers are promising because they have high values of adiabatic temperature change (Δ T S ) and isothermal entropy change (Δ S T ). However, their thermal conductivity is limited, which is a fundamental property for heat transfer. Hence, in this work, we characterized the mechanocaloric effect in natural graphite/thermoplastic polyurethane (NG/TPU) composites. The pure TPU and its NG/TPU composites were characterized by their thermal and mechanical properties. The NG/TPU composites presented Δ T S  = 8.6 K and Δ S T  = 35 J kg −1  K −1 , which correspond to a maximum reduction of 28 and 45% in the Δ T S and Δ S T , respectively, when compared to pure TPU, but with an increase of 500% in thermal conductivity. We reported no significant reduction in the Δ T S for the composites after 10 5 compression cycles. Our findings combine a large mechanocaloric effect with the unique characteristics of TPUs and the enhanced thermal conductivity of its NG/TPU composites. Graphical Abstract