Polysulfide resins,with trade name of  G4 and G112, with short and long chain lengths respectively, were used as reactive modifiers to toughen epoxy resin. The effects of molecular weights of G4 and G112 on impact resistance, dielectric constant, thermal conductivity as well as decomposition  heat and adhesion properties of toughened epoxy were investigated. The impact strength and the diel...

A dielectric constant measurement setup has been developed to measure dielectric constant of liquids using AT89C55WD microcontroller. A modified operational amplifier based AC Schering Bridge network is used to compute capacitance and hence calculate dielectric constant of liquids. This instrument system permits recording of dielectric constant of liquids at various concentrations and temperatu...

This paper presents accurate data for the physical aging of organic glasses just below the glass transition probed by monitoring the following quantities after temperature up and down jumps: the shear-mechanical resonance frequency (∼360 kHz), the dielectric loss at 1 Hz, the real part of the dielectric constant at 10 kHz, and the loss-peak frequency of the dielectric beta process (∼10 kHz). Th...

—A system for measuring the dielectric properties of cereal grains from 1 to 350 MHz with a coaxial sample holder is presented. A signal-flow graph model was used to determine the permittivity of several polar alcohols from the full two-port S-parameter measurements. At the lowest frequencies 1-25 MHz where the phase measurements are less accurate, a lumped-parameter model was used to predict t...

The field distribution, dielectric constant, and loss in a two-phase composite, in which phase A is distributed inside a square matrix of phase B, have been calculated using the finite-element method ~FEM!. The calculation was carried out by taking into account different shapes for phase A, such as circles, triangles, and rings with different sizes. The modeling by FEM in the dielectric composi...

Novel three-dimensional hierarchical flower-like TiO2/carbon (TiO2/C) nanostructures were in-situ synthesized via a solvothermal method involving calcination of organic precursor under inert atmosphere. The composite films comprised of P (VDF-HFP) and as-prepared hierarchical flower-like TiO2/C were fabricated by a solution casting and hot-pressing approach. The results reveal that loading the ...

Polycrystalline samples of Gd-modified Lead Zirconate Titanate [PGZT; Pb1-xGdx(Zr0.65Ti0.35)1-x/4O3] ceramics (where, x = 0.00, 0.06 and 0.09) were prepared using high temperature mixed oxide method at sintering temperature 1450 K. Preliminary structural analysis through X-ray diffraction technique suggests their formation in single phase tetragonal crystal system at room temperature. From the ...

Dielectric properties of composites near percolation threshold (fc) are often sensitive to thermal treatments, and the annealing temperature is usually associated with a polymer's rheological properties. In this study, the influences of the thermal treatment on dielectric properties are investigated for the polystyrene (PS) matrix composite reinforced by graphene nanoplatelets (GNP) fillers nea...

The material properties of greatest importance in microwave processing of a dielectric are the complex relative permittivity epsilon = epsilon'-jepsilon", and the loss tangent, tan delta = epsilon"/epsilon'. This paper describes two convenient laboratory based methods to obtain epsilon', epsilon" and hence tan delta of fibre-reinforced thermoplastic (FRTP) composites. One method employs a micro...