Thermal insulation and dielectric properties of aluminium phosphate-polyethersulphone layered composites

The heat resistant layer of aluminium phosphate (AlPO₄) was prepared on the surface of polyethersulphone (PES) matrix using the high temperature calcination molding process. The microstructure, chemical component and thermal stability of AlPO₄-PES layered composites were characterized by techniques of SEM, confocal laser scanning microscopy-three dimensional morphology analysis (CLSM-3D), FTIR and TGA. The influence of AlPO₄ content on the thermal conductivity and dielectric property of AlPO₄-PES layered composites was investigated. The results show that the incorporation of AlPO₄ leads to significant changes on the microscopic structure of PES matrix. And heat resistant layer of AlPO₄ and PES matrix are combined together via physical way. The thermal stability of AlPO₄-PES layered composites is obviously enhanced with increasing the AlPO₄ content, while the thermal conductivity of composites is decreased continuously. As the AlPO₄ content increases, both the dielectric constant and dielectric dissipation of AlPO₄-PES layered composites are reduced, and they exhibit excellent frequency stability in the test range of 0.1-5 MHz.