Dielectric investigation of some normal alcohols and diols dispersed in some polymeric matrices

Abstract

A series of diols and normal alcohols were dispersed in some polymeric matrices, namely, polystyrene (PS), polyethylene (PE), and poly(methyl methacrylate) (PMMA). The dielectric properties of these systems were investigated in the frequency range of 10 2 -10 5 Hz at a room temperature of 25 o C. The experimental data were analyzed according to the Fröhlich equation into two relaxation processes: The first relaxation in the lower-frequency range could be attributed to the Maxwell-Wagner effect as a result of the difference in permittivities and conductivities of the investigated systems. The second relaxation in the higher-frequency range could be attributed to an intramolecular motion involving the rotation of various segments of the chain about the C-C bond accompanied by movement of the main dipoles for either diols or alcohols. The presence of the phenyl ring in the PS matrix may hinder such rotation when compared with the other matrices. The dielectric properties were also investigated for PMMA blended with either PS or PE at different ratios before and after the addition of small quantities of ethanediol. The interaction that might be expected between PMMA and PS in the blend may affect the rotation of the ethanediol chain in the blend matrix. The dielectric data as well as the data obtained from the calculated heat of mixing show that the investigated blends are incompatible. The addition of ethanediol to such blends gives the possibility that a large number of dipoles can be impregnated into the blend matrix and the problem of phase separation could be solved.

Dielectric study of methyl methacrylate-alcohol mixtures by Time Domain Reflectometry at 293 K

“…It is also noticed that the e 0 was gradually decreased by increasing the number of carbon atoms in the alkyl chain of alcohols. This trend could be attributed to the decrease in the number of dipoles in the complex, which may lead to a decrease in the molar volume of the rotated molecule [20]. It is also noticed that, though the t value of mixtures lie between the individual component values, they are in general, different from the averaged value because of the change in the molecular environment and in the size of the relaxing unit.…”

Effect of molecular weight on dielectric properties of polyvinyl alcohol films

“…This may be due to OH chain molecular polarization; then, the trend was found decreasing at 1 MHz frequency ϭ 14.31; at higher frequency, the values shows the proportionality relation with applied bias voltage. 10 PVA film of higher molecular weight shows the dielectric polarization maximum at lower frequency. Figure 2 shows the dielectric loss of PVA film higher molecular weight; dielectric loss (Ј) was found maximum at lower frequency with values Ј ϭ 0.725 for all bias potentials.…”

“…Altogether, numerous studies have been carried out on various types of alcohols as pure liquid, in solution and even in the solid state. 10 Figure 1 shows the plot of dielectric constant () as function of frequency for high molecular weight of PVA film. Values was maximum at 20 Hz frequency, ϭ 15.1 at 0 V bias potential and ϭ 18.97 at 40 V bias potential.…”

Dielectric relaxation study of ethyl acrylate-alcohol mixtures using time domain reflectometry

“…It has also been noticed that the ε 0 has gradually decreased by increasing the number of carbon atoms in the alkyl chain of alcohols. This trend could be attributed to the decrease in the number of dipoles in the complex, which may lead to a decrease in the molar volume of the rotated molecule [26]. It is also noticed that, though the τ values of mixtures lie between the individual component values, they are in general different from the averaged value because of the change in the molecular environment and in the size of the relaxing unit.…”