Physical-chemical and chemical modification of PVC and their effect on the electrical properties of the polymer

TL;DR

This study explores chemical modifications of PVC, such as plasticization and thermal dehydrochlorination, to enhance its electrical conductivity, and investigates doping methods to analyze the conduction mechanisms related to conjugated double bonds.

Contribution

It introduces a novel doping method to analyze electrical conduction in modified PVC and identifies the formation of a barrier layer affecting conductivity.

Findings

Doping with iodine significantly increases electrical conductivity.

Barrier layers form at dehydrochlorinated PVC interfaces, affecting conduction.

Surface heterogeneity correlates with the presence of conjugated double bonds.

Abstract

The possibilities to increase the static conductivity of PVC compared to the initial antistatic level, for PVC plasticate obtained with effective plasticizer - a so called modifier of type A, and partial thermal dehydrochlorination for formation of a copolymer with a system of conjugated double bonds are investigated. To analyze the dependence of electrical conductivity from double conjugated bonds the doping method is proposed, in which a chemically active dopant is embedded between two thin films of the polymer sample, not touching, and, accordingly, not interacting with the metal electrodes. In this scheme it is found, that the for folding of two layers of partly dehydrochlorinated PVC on the border between them the barrier layer is formed, which can be eliminated by doping with iodine giving significant increase in electrical conductivity. This layer does not arise in the case of type A modifier plasticized PVC. The presence of such layer can be interpreted as a sign of the near-surface spatial heterogeneity associated with the presence of conduction mechanism of double conjugated bonds.