Dielectric study on size effects in polymer laminates and blends (original) (raw)

Studies of Dielectric Constant of Some Polymer/Ceramic Composite Materials: A Conformational Study

Polymer/ceramic composites are the most promising embedded capacitor material for organic substrates application. Predicting the effective dielectric constant of polymer/ceramic composites is very important for design of composite materials. In the present paper the dielectric constant has been evaluated by various mixing rules/models for polymer-ceramic composites and compared with experimental values taken from literature. Results have been discussed on the basis the value of average percentage deviation of dielectric constant.

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.

Effect of interphase interactions on the dielectric behaviour of polycarbonate/poly(styrene-co-acrylonitrile) blends

Polymer Bulletin, 2000

Frequency and temperature dependences of the complex permittivity * (= 'i ", ' is the real and " imaginary component, respectively) were investigated for blends of polycarbonate/poly(styrene-co-acrylonitrile) (PC/SAN). In the blends, two-processes corresponding to the main transitions of PC and SAN were found; for SAN at concentrations c SAN 20 wt% and for PC for c PC 40 wt%. The Havriliak-Negami shape parameters describing the frequency dependence of ' and " are virtually independent of temperature and composition. Slight shift of temperature or frequency positions ofprocesses found for blends from those found for neat polymers with composition of blends indicated partial miscibility of components. The concentration dependences of ' and " at low frequencies and high temperatures could be described with the Böttcher equation from which it followed that percolation threshold takes place for SAN inclusions at c SAN 30 wt%. Both the reduced dielectric strength T and the reduced Onsager term O t /c SAN (or O t /c PC) in dependence on the blend composition could be qualitatively described by the Böttcher equation as well.

Tuning of Dielectric Properties of Polymers by Composite Formation: The Effect of Inorganic Fillers Addition

Journal of Composites Science

Polymer blend or composite, which is a combination of two or more polymers and fillers such as semiconductors, metals, metal oxides, salts and ceramics, are a synthesized product facilitating improved, augmented or customized properties, and have widespread applications for the achievement of functional materials. Polymer materials with embedded inorganic fillers are significantly appealing for challenging and outstanding electric, dielectric, optical and mechanical applications involving magnetic features. In particular, a polymer matrix exhibiting large values of dielectric constant (ε′) with suitable thermal stability and low dielectric constant values of polymer blend, having lesser thermal stability, together offer significant advantages in electronic packaging and other such applications in different fields. In this review paper, we focused on the key factors affecting the dielectric properties and its strength in thin film of inorganic materials loaded poly methyl meth acryla...

Dielectric study of poly(methylacrylate) plus poly(4-hydroxystyrene) or plus poly(4 hydroxystyrene- co-4-methoxystyrene) blends near the glass transition

Polymer, 1997

The dynamics of blends of poly(methylacrylate) (PMA)+ poly(4-hydroxystyrene) (P4HS) and poly(4hydroxystyrene-co-4-methoxystyrene) (MP4HS) have been studied by dielectric relaxation in the frequency range 20 < w/Hz < 105. The results have been analysed in terms of the Havriliak-Negami function plus a conductivity contribution. The time-temperature superposition principle breaks down for the blends, while it seems to be valid for PMA. The width of the relaxation region increases with the content of P4HS or MP4HS, in accordance with previous dynamic mechanical relaxation data. For a given composition, the data of the blends follow the scaling curve proposed by P. W. Dixon (Phys. Rev. Left., 1990, 42, 8179), however in the low frequency region each sample follows a different scaling curve, which slope is related to the c~ parameter of the Havriliak-Negami function. The increase of the width of the relaxation curves with decreasing the PMA content can be well correlated by the coupling model when a gaussian distribution of coupling parameters is taken into account. © 1997 Elsevier Science Ltd.

Polymer Nanocomposite Dielectrics – The Role of the

Dielectrics and …, 2005

The incorporation of silica nanoparticles into polyethylene increased the breakdown strength and voltage endurance significantly compared to the incorporation of micron scale fillers. In addition, dielectric spectroscopy showed a decrease in dielectric permittivity for the nanocomposite over the base polymer, and changes in the space charge distribution and dynamics have been documented. The most significant difference between micron scale and nanoscale fillers is the tremendous increase in interfacial area in nanocomposites. Because the interfacial region (interaction zone) is likely to be pivotal in controlling properties, the bonding between the silica and polyethylene was characterized using Fourier Transformed Infra-red (FTIR) spectroscopy, Electron Paramagnetic Resonance (EPR), and X-ray Photoelectron Spectroscopy (XPS) The picture which is emerging suggests that the enhanced interfacial zone, in addition to particle-polymer bonding, plays a very important role in determining the dielectric behavior of nanocomposites.