Dielectric Properties of Composites of Natural Rubber and Keratin Fibre from Chicken Feather

The dielectric properties of chicken feather fibre-natural rubber (CF-NR) composites have been studied at varying frequencies. The effects of alkali treatment, thermal treatment and a three-component dry bonding agent consisting of hexamethylenetetramine, resorcinol and nano silica (HRS) on these properties were studied. Dicumyl peroxide (DCP) and sulphur were used as curing systems in the preparation of the composites. Fibre filled composite systems have higher values of dielectric constant than the gum (unfilled) sample. This is due to the polarization exerted by the addition of fibres into the matrix. The dielectric constant decreases with frequency due to the dropping out of dipolar and interfacial polarization at higher frequency. The dielectric constant values of composites containing alkali treated chicken feather fibres (ACF) were higher because of the increase in number of polar groups after the treatment. The carbonized chicken feather fibre (CCF) incorporated NR composites have highest dielectric constant values because they consist of conducting material in an insulating matrix which leads to interfacial polarization. The dielectric constants of sulphur cured composite samples are higher than the corresponding DCP cured ones. The addition of fibres and with the incorporation of the bonding agents causes an increase in the dielectric constant and decreases the volume resistivity of the composites.