Effects of oil palm and montmorillonite nanofillers on stiffness and interfacial adhesion of kenaf/epoxy hybrid nanocomposites

The dielectric properties of bio-hybrid composites based on natural Oil Palm Empty Fruit Bunch (OPEFB), montmorillonite (MMT) and organomodified montmorillonite (OMMT) nanoclay reinforced kenaf (KF)/epoxy are reported in this study. The molecular mobility, interfacial adhesion between KF fibers and epoxy resin matrix, and fragility near the glass transition temperature were evaluated using Broadband dielectric spectroscopy over a wide temperature range from 20 to 180°C and a frequency range from 0.1 Hz to 1 MHz. Obtained results indicated different relaxations: the α glass-rubbery transition and the interfacial polarization between KF/epoxy called Maxwell-Wagner-Sillars polarization “MWS(KF/epoxy)” whose amplitude, position and dielectric strength ∆ε_{MWS(kenaf/epoxy)} depends on the type of the added nanofillers. ∆ε_{MWS(kenaf/epoxy)} decrease for all the measured temperatures while the activation energy E_a of the α-process and rigidity increase when the nanocharges are introduced. It has been found that the OPEFB, MMT, and OMMT are uniformly distributed in the matrix and act as a link between the KF fibers and the epoxy resin via the formation of new C—O and Si—O—Si bonds.