Giant Reversible Barocaloric Effects in Nitrile Butadiene Rubber around Room Temperature

Elastomers have shown to be promising barocaloric materials, being suitable candidates for solid-state cooling devices. Moreover, this family of polymers presents additional advantages, such as their low cost and long fatigue life. In this context, we investigated the barocaloric effects in nitrile butadiene rubber (NBR) in a large range around room temperature. Applied pressures up to 390 MPa on NBR yield giant reversible isothermal entropy change (ΔS_T) and adiabatic temperature change (ΔT_S), reaching the maximum absolute values of 59(6) J kg^–1 K^–1 at 303 K and 16.4(2) K at 323 K, respectively, for a pressure change of 390 MPa. Besides, both ΔT_S and ΔS_T have shown to be rather reversible in a wide range of temperatures. For the first time, it was reported the influence of the glass transition on ΔS_T. Our study evidences the potential of NBR for room-temperature cooling applications based on the barocaloric effect.