Mechanism of dc electrical conductivity in poly(vinyl chloride)

Abstract

Dc conductivity measurements were performed as a function of temperature on unplasticized poly(vinyl chloride) and on PVC plasticized with various amounts of dioctylphthalate. The conductivity curves consist of two or three straight‐line segments denoted I, II, and III with increasing of temperature. The intersection of segments I and II occurs at the glass‐transition temperature Tg. The slope in region I is independent of the DOP concentration, while the slope in region II decreases slowly with an increase in the amount of DOP. No dependence of the conductivity on the molecular weight was found. From the conductivity curves, activation energies were evaluated below and above Tg. These satisfactorily coincide with those determined by dielectric loss or by electrical transient phenomena. A dc conduction mechanism is proposed based on electronic hopping favored by the micro‐Brownian motions responsible for dielectric losses. These motions involve smaller chain lengths below than above Tg. The experimental results are discussed and interpreted in terms of the proposed mechanism.

Electrical conductivity in ionic complexes of poly(ethylene oxide)

“…Lupu et al 10 have recently studied the temperature dependence of electrical conductivity in poly(viny1 chloride)-dioctyl phthalate mixtures. They observed the usual transition at Tg, but in mixtures having greater than about 10 wt-% plasticiser, a second transition from a high activation energy, intermediate temperature process to a low activation energy, high temperature process was observed.…”

Electrical conduction in (polyvinyl alcohol/glycogen) blend films

“…Various mechanisms, such as Schottkey emission [5][6][7], Poole-Frenkel emission [8,9], space-charge limited conduction [10], and hopping conduction [11,12], have been suggested for the charge transport. More recently, consid-erable interest has been shown on the effect of doping on the transport properties of polymers [13][14][15][16].…”

The glass transition behaviour of salted nylon 6

“…in terms of Arrhenius plot. Such curves allow to calculate the glass transition temperature as the break point in the low temperature region (4,9).…”

“…A more difficult analysis is needed for the stress relaxation results, from which the ghss transition temperature has been evaluated as the maximum in the plot of the isochronal relaxation rate vs. temperature (9). These curves have been calculated for 1, 10, 10 2 and 10 3 sec., and then the relative frequencies are 1, 10 -1 , 10 -2 and 10 -3 Hz.…”