Electrocaloric properties of ferroelectric P(VDF-HFP)/PU composites

Abstract

Electrocaloric (EC) cooling is one of a new cooling technology for refrigeration and air conditioning systems. This EC cooling is very interesting, not only because their higher energy conversion efficiency, but also because it is a green technology. Poly(viny lidene fluoride hexafluoropropylene), P(VDF-HFP) blended with polyurethane, PU was studied on an electrocaloric properties. All polymer composites were prepared by solution tape casting. The microstructure and crystallinity of P(VDF-HFP)/PU composites were observed by FTIR and XRD. Hysteresis loop of P(VDF-HFP)/PU composite films was also investigated with various operation temperature near Curie temperature, and their adiabatic temperature change, ΔT based on electrocaloric effect was measured by indirect method with helping of Maxwell relation. For the experimental results, hysteresis loop of all samples was observed and showed as normal ferroelectric above the F-P transition, as relaxor ferroelectric at near room temperature. Besides, the adiabatic temperature change, ΔT of P(VDF-HFP)/PU composites gradually increases with increasing PU content. It was be found that the maximum of adiabatic temperature changes of P(VDF-HFP)/PU composites with ratio 8.0:2.0 at obtained more than 22 °C, which higher than pure P(VDF-HFP). Final, the increasing ΔT will be discussion on relationship of microstructure, phase transition and crystallinity of obtained P(VDF-HFP)/PU composite.