Dielectric Properties of Industrial Polymer Composite Materials (original) (raw)
Related papers
Journal of Vinyl and Additive Technology, 2018
This article presents the study of dielectric properties of synthetic and natural fiber reinforced epoxy composites. Bamboo and glass fibers were both chopped and woven. These fibers were then used for reinforcing epoxy, with different fiber loadings. The dielectric properties of these composites were studied with reference to their fiber loadings, frequencies, and chemical treatment of the natural fibers at room temperature. It was found that dielectric properties increased with the increase in the concentration of fibers filled in the epoxy matrix, for the entire frequency range. This was due to the increase in the orientation and interfacial polarization. The treated fiber composites had lower dielectric properties due to decreased hydrophilicity of the natural fiber. The chopped glass fibers reinforced epoxy composites have the highest dielectric constant, among all tested composites.
Dielectric Properties of Wood-Polymer Composites
2010
re and " e and dielectric loss factor tgδ for various electric field frequencies and at different temperatures. The results show that the dielectric properties are heavily influenced by the filler content with very high registered values in the case of low frequency electric fields and high temperatures. It can be ascertained that samples having a polypropylene matrix have superior electric properties than those having a polyethylene matrix. Finally, the opportunity for utilization within low voltage and industrial frequency electrical engineering applications of the tested composite materials is shown.
Dielectric Spectroscopy of Composites of Epoxy Resin
Journal of Basic & Applied Sciences, 2013
The dielectric behavior of composite of epoxies having different composition of prepolymer and epoxy equivalent is investigated in the frequency range 1E-1Hz to 1E5Hz at room temperature. The measurements presented consist of two sets of sample of epoxy resin with two different proportions 1:1 and 1:0.5 of resin and hardener. Samples having different proportion of resin and hardener shows low frequency dispersion (LFD) in the frequency range below 3 KHz at small thickness (less than 0.38mm). At large thickness the sample response is similar for the two different proportions.
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.
Journal of Applied Polymer Science, 2013
In this work, we undertook a comparative study of the dynamic dielectric analysis of two composites: natural-fiber-reinforced unsaturated polyester (NFRUP) and E-glass-mat-reinforced unsaturated polyester (EGMRUP). In both composites, two common relaxation processes were identified, the first of which was the a-mode relaxation associated with the glass transition of the matrix. The second one was associated with conductivity that occurred because of the carriers' charge diffusion and was observed at temperatures above the glass transition and at low frequencies. However, the interfacial or Maxwell-Wagner-Sillars polarization was noticed only in the NFRUP composite. This dielectric study also revealed that compared to E-glass fibers, natural fibers enhanced the thermal insulation in the composite. Also, the study of the fiber adhesion in the matrix with scanning electron microscopy, differential scanning calorimetry, and tensile testing revealed a great compatibility of the fibers with the matrix in both composites.
Dielectric Properties Modeling of Composite Materials
Tailoring dielectric properties of engineering materials has become very important since many radio wave propagation problems and remote sensing applications depend on correct values of these material properties. Prediction of material dielectric constant and loss tangent is of paramaunt importance. Polymer matrix composite materials are excellent candidates for these applications. In this paper analytical method for material dielectric constant and loss tangent prediction is preseneted. The model is experimentally verified for E-glass fibers embedded in epoxy matrix. Test results for 100 kHz to 1 MHz frequency range are presented.
Journal of Composites Science
The characterization of the dielectric properties of wood–polymer composites (WPCs) is essential to understand their interaction with electromagnetic fields and evaluate their potential use for new applications. Thus, dielectric spectroscopy monitored the evolution of the dielectric properties of WPCs over a wide frequency range of 1 MHz to 1 GHz. WPCs were prepared using mixtures of different proportions (40%, 50%, and 60%) of wood and bark fibers from various species, high-density polyethylene, and maleated polyethylene (3%) by a two-step process, extrusion and compression molding. Results indicated that wood fibers modify the resistivity of polyethylene at low frequencies but have no effect at microwave frequencies. Increasing the fiber content increases the composites’ dielectric properties. The fibers’ cellulose content explains the variation in the dielectric properties of composites reinforced with fibers from different wood species. Indeed, composites with high cellulose con...
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...
Journal of Applied Polymer Science, 2012
It is well known that most of the dielectric failures occur in high voltage equipment due to absorption of moisture by the insulating material from the environment. Hence, the effect of absorbed moisture on electrical and mechanical properties of silica-unsaturated polyester resin (UPR) composites has been evaluated. The absorption of moisture in silica-UPR composites does not show any significant change in electrical and mechanical properties. The effect of acetone and water absorption on silica-UPR composites was determined and it was that found silica-UPR composite shows higher acetone absorption when compared with water. The differential scanning calorimetry and thermal gravimetric analysis studies of silica-UPR composites show no significant change in glass transition temperature using prehumidified (0-95% RH) silica filler. As there is no significant change in thermal and mechanical properties after exposure to humid conditions, it can be concluded that water does not penetrate inside the polymer matrix. Hence, the silica particles are the best choice to use as filler in UPR matrix for UPR composite used in electrical equipment. The developed silica-UPR composite was successfully used in the preparation of medium voltage inductive transformers.
Polymers
The influence of various types of nanoparticle fillers with the same diameter of 20 nm were separately incorporated into a single component impregnating resin based on a polyesterimide (PEI) matrix and its subsequent changes in complex relative permittivity were studied. In this paper, nanoparticles of Al2O3 and ZnO were dispersed into PEI (with 0.5 and 1 wt.%) to prepare nanocomposite polymer. Dielectric frequency spectroscopy was used to measure the dependence of the real and imaginary parts of complex relative permittivity within the frequency range of 1 mHz to 1 MHz at a temperature range from +20 °C to +120 °C. The presence of weight concentration of nanoparticles in the PEI resin has an impact on the segmental dynamics of the polymer chain and changed the charge distribution in the given system. The changes detected in the 1H NMR spectra confirm that dispersed nanoparticles in PEI lead to the formation of loose structures, which results in higher polymer chain mobility. A shif...