Dielectric Spectroscopy of Composites of Epoxy Resin (original) (raw)

Dielectric Properties of Filled Composites of Epoxy Resin

Journal of Basic & Applied Sciences, 2014

The addition of fillers in composite of epoxies, improves the dielectric response of the epoxies. The dielectric properties of unfilled and filled composites of epoxy resins have been studied as a function of thickness in the frequency range 10-1 Hz to 10 5 Hz at room temperature. The response of the unfilled samples shows that the composites behave as an insulator for all thickness. In filled composites at small thickness (0.32 mm) the response shows a loss peak in low frequency regime. The peak is broader than the Debye loss peak which is obscured by the dc conductance. At frequencies greater than p the response shows a well defined power law behaviour after the subtraction of C. Similar behaviour has been observed at different thickness.

DIELECTRIC PROPERTIES OF CURED EPOXY WITH TETA

The dielectric properties of epoxy resin (diglycidylether of bisphenol A, DGEBA) with triethylene tetramine (TETA) were investigated by the complex impedance spectroscopy technique. The dielectric parameters have been measured using parallel plate capacitor method using HP 4192A LF Impedance Analyzer in the frequency range from 1 MHz to 13 MHz and in the temperature range from 25 C to 120C. Variations of real (e1) and imaginary (e2) parts of dielectric constants of material with frequency and temperature have been studied. The general behaviours of e1 and e2 are found to stable with increasing frequency up to 8 MHz. Over this frequency, an anomaly behaviours of e1 and e2 were reported except 25 C. e1 increase from about 9 MHz to approximately 10 MHz. e2 start to rapidly decrease about 8.5 MHz and they have been a deep about 9.7 MHz. e2 increases from about 9.7 MHz to 10 MHz. their behaviours are smooth above 10 MHz. When the Cole-Cole plots are investigated, e2 increase with e1 below 9 MHz and they are smooth with e1 above 10 MHz. But there are appeared rings between approximately 8 MHz-10 MHz.

Dielectric Properties of Industrial Polymer Composite Materials

2005

Frequency and temperature dependence of dielectric constant ε and dielectric loss ε in pure polyester resin and polymer composites with various types of glass fiber are studied in the frequency range 330 Hz-3 MHz and in the temperature range 25-150 • C. The experimental results show that ε and ε increased with the addition of glass fiber in polyester resin. The value of ε decreased with increasing frequency, which indicates that the major contribution to the polarization comes from orientation polarization. Dielectric loss peaks were also observed in the composite materials at high temperature due to Tg of polyester. The value of ε increased with increasing temperature, and is due to greater freedom of movement of the dipole molecular chains within the polyester at high temperature.

Influence of absorbed moisture on the dielectric properties of epoxy resins

2010

The dielectric response of two bisphenol-A epoxy resin systems Araldite CY1301 (Tg ~ 50C) and Araldite CY1311 (Tg ~0C) was studied at different levels of relative humidity. The dielectric measurements were carried out over the frequency range 1 mHz to 100 kHz and the results were characterised in terms of conduction and relaxation processes. The characteristic parameters (frequency and magnitude) of all processes have found to be moisture dependent. The experimental data were fitted to a Dissado-Hill model and the form of the water dependence was characterized for all components of the dielectric response. The influence of possible interfacial features on the measured results is discussed.

Dielectric Properties of Series Joined Silicone Rubber and Epoxy Resin Formulations

7th International Conference on Mechanical and Industrial Engineering, 2022

Dielectric frequency spectroscopy of polymer materials were done in laboratory. The aim was to investigate the (i) differences in dielectric losses of the industrially manufactured silicone rubbers against laboratory manufactured silicone rubbers, (ii) differences in dielectric losses for the epoxy resin samples manufactured in laboratory, but with different curing time, and (iii) differences of dielectric losses between each single polymer to the losses of the series joined specimens of the two polymers. The measurements were done using the Insulation Diagnostics System in laboratory at ambient room conditions. It has been found out that for different frequency ranges, silicone rubber manufactured industrially differ with the laboratory manufactured specimens. The series joined specimens show higher influence of the silicone rubber in both curve shape, and values of losses at frequencies lower than 1 Hz. At frequencies lower than 1 Hz the joined specimen losses are higher than losses for epoxy resin and lower than those for silicone rubber. At frequencies higher than 1 Hz the losses of the joined samples are close but slightly lower to those of epoxy resin and higher than those of silicone rubbers. Lastly, the curves of the joined specimens have shapes which strongly resembles those of the silicone rubbers.

Dielectric properties of cured epoxy resin+ poly (ethylene oxide) blends

Journal of non- …, 2005

Epoxy resin (ER) + poly(ethylene oxide) (PEO) blends cured with 4,4 0 -diaminodiphenyl-methane were studied by thermally stimulated currents and dielectric relaxation spectroscopy. The results confirm components miscibility with dielectric glass transition temperature-composition dependence obeying the empirical Gordon-Taylor G-T equation with k = 0.38. Positive departures from the G-T curve appear at high PEO loadings due to crystallization of the linear polyether. Subtle perturbations of the local-chain relaxation dynamics and the relatively low k estimate advocate for weakened intermolecular-specific interactions in the miscible blends, compared with the intramolecular self-association of hydroxyls in pure ER, suggesting structural similarity as the primary driving force for phase miscibility.

Dielectric relaxations investigation of a synthesized epoxy resin polymer

A diglycidylether of bisphenol A (DGEBA) epoxy resin was synthesized, and cured with 3, 3′- diaminodiphenyl sulfone (DDS) at a curing temperature of 120 ◦C. The relaxation properties of the realized polymers were studied by two complementary techniques: dielectric relaxation spectroscopy (DRS), in the temperature range 173–393K and in the frequency interval 10−1–106 Hz, and thermally stimulated depolarization current (TSDC) with a windowing polarization process. Current-voltage (I-V) measurements were also carried out to study interfacial relaxations. Dielectric data were analyzed in terms of permittivity and electric modulus variations. Three relaxation processes (,  and ) have been identified. They were found to be frequency and temperature dependent and were interpreted in terms of the Havriliak-Negami approach. Relaxation parameters were determined by fitting the experimental data. The temperature dependence of the relaxation time was well fitted by the Arrhenius law for secondary relaxations, while the Vogel-Fulcher-Tamann model was found to better fit the  (T) variations for  relaxation. We found 0 = 4.9 10−12 s, 9.6 10−13 s and 1.98 10−7 s for ,  and  relaxations, respectively. The obtained results were found to be consistent with those reported in the literature. Due to the calculation of the low-frequency data of dielectric loss by the Hamon approximation, the Maxwell-Wagner-Sillars (MWS) relaxation was highlighted.

Dielectric Properties of Laminating Resin

2018

Resin has been used in industries because of different essence. The main objective of the thesis was to develop a module to study the dielectric constant change during wetting and curing and to study if the wetting of the composite results in an apparent change in capacitance due to a partial or complete displacement of all cavities air by cavity resin. Three different sensors, big finger capacitor with photolithography, sprial and finger sensor were developed inorder to perfrom the research. The designing of the sensor was done with Eagle and Audacity was used to collect the data. Lamination were done with all sensors and results were analysed. For big finger capacitor, lamination was done on the top of it and lamina was first constructed and then the spiral and finger sensors were placed on top. The results analysed illustrates that at lower frequencies the resin molecules oscillates more as compared to the higher frequencies and oscillation stops as the resin gets cured. The demo...

Dielectric spectroscopy of epoxy/glass composite materials

Annual Report Conference on Electrical Insulation and Dielectric Phenomena, 2002

Glass fibre reinforced epoxy (GFRE) material is used in pressboard transformers for optical telecommunication systems, typically at voltages between 1 to 2kV. A programme has been set up to follow the electrical ageing of the GFRE through dielectric and space charge (PEA) measurements. Here we report on the characterisation of the GFRE prior to ageing made by means of linear dielectric spectroscopy. Preliminary results for the aged samples show differences in dielectric response that could be related to de-bonding at the epoxy-fibre interfaces observed in some failed samples.