Dielectric properties and interfacial adhesion of jute, kenaf and E-glass fabrics reinforcing epoxy composites

In this work, three laminated Epoxy composites reinforced with five woven layers of E-glass fabrics, jute fabrics and kenaf fabrics were characterized by broadband dielectric spectroscopy. The dielectric analysis was performed in temperature range from 20 to 180 degrees C and frequency range from 0.1 Hz to 1 MHz. The Epoxy matrix shows the presence of four relaxation processes, which are attributed to the beta relaxation process, alpha relaxation process, the quasi-continuous conduction and the dc conduction. In the laminated composite reinforced with the E-glass fabric, only one additional relaxation process was detected, which was attributed to the interfacial polarization effect known as Maxwell-Wagner-Sillar polarization. However, for the laminated composites reinforced with jute and kenaf fabrics, two additional relaxation processes were observed. While the first one was associated with the water dipoles polarization imputed to the presence of polar water molecules in jute and kenaf fabrics, the second was linked to the interfacial polarization effect. The latter phenomenon was investigated by an analytical study using the Havriliak-Negami model. The best adhesion between reinforcement and Epoxy matrix was obtained with E-glass fabrics. This study was supported by the thermal properties using a differential scanning calorimetry. POLYM. COMPOS., 40:2142-2153, 2019. (c) 2018 Society of Plastics Engineers