Large barocaloric effects at low pressures in natural rubber

TL;DR

This study demonstrates that vulcanized natural rubber exhibits large barocaloric effects at relatively low pressures, making it a promising material for solid-state refrigeration applications.

Contribution

It provides direct measurements of barocaloric effects in natural rubber and compares its performance favorably with other polymers, highlighting its potential for cooling technologies.

Findings

Temperature change ({}T) exceeds 10 K at 173 MPa

Isothermal entropy change ({}ST) of 21 J/kg·K at 43.4 MPa

Natural rubber outperforms PVDF-TrFE-CTFE in similar conditions

Abstract

Barocaloric effect in vulcanized natural rubber (V-NR) has been investigated. Direct measurements of the temperature change ({\Delta}T) around room temperature (283-333 K) resulted in large values, above 10 K, for a pressure change of 173 MPa. A power law was proposed to fit {\Delta}T as function of the maximum pressure, showing to be suitable for the barocaloric effect in V-NR. Strain was measured as a function of temperature at constant pressures in order to obtain the isothermal entropy change ({\Delta}ST). At 293 K, we obtained a {\Delta}ST of 21 J.kg-1K-1 for a pressure change of only 43.4 MPa. The results presented in this work are compared with those reported recently for PVDF-TrFE-CTFE polymer, showing a better barocaloric performance for V-NR in similar temperature and pressure ranges. These findings evidence the high potential of V-NR for application in solid-state refrigeration based on confined compression, opening new possibilities for i-caloric materials.