Elektrokalorik soğutucu uygulamaları için ferroelektrik seramik-polimer nanokompozitler

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" Elektrokalorik soğutucu uygulamaları için ferroelektrik seramik-polimer nanokompozitler "
Tokkan, Melike Adem, Umut

Document Type	:	Latin Dissertation
Language of Document	:	English
Record Number	:	1112234
Doc. No	:	TLpq2522829839
Main Entry	:	Adem, Umut
	:	Tokkan, Melike
Title & Author	:	Elektrokalorik soğutucu uygulamaları için ferroelektrik seramik-polimer nanokompozitler\ Tokkan, MelikeAdem, Umut
College	:	Izmir Institute of Technology (Turkey)
Date	:	2020
student score	:	2020
Degree	:	Master's
Page No	:	85
Abstract	:	In this study, nanocomposites consisting of the polymer matrix and nanometer sized ceramic supporting phase were produced for electrocaloric cooling applications, which show potential as alternative refrigerant system. The aim of this study was to be able to estimate adiabatic temperature change (ΔT) of the composites by measuring saturated hysteresis loops for the composite materials that allow accurate calculation of the ΔT using the indirect method based on Maxwell's relations. Ba0.94Ca0.06Ti0.925Sn0.075O3(BCST) composition ceramic was used as the supporting phase of the composite and P(VDF-TrFE)(55-45) co-polymer was chosen as the matrix. The ceramics were synthesized, as pellets by conventional solid-state method. Ferroelectric nanocomposites were manufactured by solution casting method by adding 5, 7.5, 10 volume percent of the ceramic powder, which was obtained by grinding the pellets by using ball milling. Phase analysis of all materials done using X-ray Diffraction method. Fourier Transform Infrared Spectroscopy was used to clearly understand the phase structure of polymer. Scanning electron microscopy was used for understand the distribution of ceramic particles in polymer matrix. Dielectric constant-dielectric loss and ferroelectric hysteresis loops were measured as a function of temperature for the electrical characterization of the materials. Adiabatic temperature change under electric field (ΔT) of the materials were calculated based on Maxwell's equations indirectly using the temperature dependent electrical polarization data. The dielectric constant and electrical polarization of the polymer matrix have increased with the addition of ceramic particles. The hysteresis loops of thebn pure polymer and composites were saturated, therefore the temperature change can be calculated accurately with the indirect method. Maximum ΔT was calculated on the composite having 10vol% ceramic particles. (6.964K at 900 kV/cm).
Subject	:	Copolymers
	:	Dielectric properties
	:	Energy storage
	:	Ferroelectrics
	:	Fourier transforms
	:	Nanocomposites