The Preparation Of Nylon Complex As Novel Electrocaloric Material And The Study Of Its Electrocaloric Effect

Electrocaloric effect?ECE?is reversible adiabatic temperature change??T?and isothermal entropy change??S?that occurs in polar material upon application of an external electric field,and the polar material is kown as electrocaloric material.A novel solid-state refrigeration technology designed based on the refrigeration cycle of ECE,which is high energy efficient,environmentally friendly,lightweight and convenient,will promisingly replace vapor-compression to be the core technology for the next refrigeration devcies.Inthiswork,nyloncomplexesweredesignedonthebasisof amorphous-crystalline transition of nylon complexes upon application of an external electric field from different entropy change.The fundamental of ECE for nylon complexes was analyzed in detail.The theoretical calculation method of?T and?S was put forward,and?T and?S of nylon 6 complex were calculated as 147.5 K and826.1 J kg^-1K^-1,recpectively.According to all the traditional ferroelectric materials,the?S and?T values of nylon 6 complex is the highest.Nylon 6/CaCl₂ film was prepared by melt-blending process and calendaring molding,and nylon 6 complex happened to be amorphous when the volume fraction of CaCl₂ reached 5%.Fourier-transform infrared spectrum and X-ray photoelectron spectrum were employed to characterize the complexation between amid group of nylon 6 and CaCl₂,the results showed that the amorphous nylon6 was attributed to the destruction of hydrogen bonds induced by the complexation between amid group and Ca²⁺.Microcalorimeter was employed to indirectly measure the ECE of nylon6/CaCl₂ film upon application of 0.8 kV cm^-1electric field.The reaults showed gaint ECE of 18.2 K,hence the electrocaloric strength was calculated as 22.8 K cm kV^-1which was about 100 times higher than all the reported electrocaloric materials.Insitu X-Ray diffraction and inductively coupled plasma-optical emission spectrometer were employed to characterize the microstructure change of nylon 6/CaCl₂ film during ECE.The results showed the real existence of amorphous-crystalline transition,decomplexation and recomplexation between amid group and Ca²⁺,migration and moving back of Ca²⁺.Through preparing mixtures of nylon 6,CaCl₂ and chlorohydrin with different ratios,nylon 6/CaCl₂ gel was discoved only in the mixtures of which the volume fraction of CaCl₂ was 5%.Fourier-transform infrared spectrum and X-Ray diffraction were employed to investigated the structure of nylon 6/CaCl₂ gel.The results showed that the crosslinking function of partial crystal region and complexation between amid group and Ca²⁺led to the gel structure.The indirect measurement method of temperature change was used to measure the ECE of nylon 6/CaCl₂ gel block upon application of 0.8 kV cm^-1electric field.The reaults showed?T of 1.8 K,hence?T of equal amout of nylon 6/CaCl₂ complex was calculated as 17.9 K which is approximatively equal to the former measured by microcalorimeter.Insitu X-Ray diffraction and inductively coupled plasma-optical emission spectrometer were employed to characterize the microstructure change of nylon 6/CaCl₂ gel block during ECE.The results also showed the real existence of amorphous-crystalline transition,decomplexation and recomplexation between amid group and Ca²⁺and migration and moving back of Ca²⁺.