Dynamic dielectric properties and the γ transition of bromine doped polyacrylonitrile

Abstract

Abstract. Based on monitoring the γ process (the lowest temperature-relaxation) in polyacrylonitrile (PAN) by dynamic dielectric spectroscopy, new evidence for the formation of a charge transfer complex between bromine dopants and nitrile groups is presented. The experimental work is carried out on PAN and nitrile polymerized PAN with and without bromine doping and the effects of these factors on the γ process are measured. Nitrile polymerization results in diminishing of the γ process and in a 15% increase in its activation energy, whereas bromine doping produces splitting of the original γ process in PAN -coupled with a significant activation energy increase -and its complete disappearance in nitrile polymerized PAN. Both the splitting of the γ process and the higher activation energy reflect bromine-nitrile adduct formation.

The Electrical Conductivity of Graphite Nanoplatelet Filled Conjugated Polyacrylonitrile

“…[7][8][9] This polymer is attractive, owing to its ability to form a conjugated imine system (cPAN) by polymerization of the pending nitrile groups, to produce a ladder-type polymer, upon heating the polymer to temperatures above 180 8C. [10][11][12] GNPs are nanoparticles with a plate-like structure obtained by exfoliating natural flake graphite into very high aspect ratio particles, which renders them ideal as fillers for conductive polymer nanocomposites and for different electrical applications.…”

Tunable dielectric properties in polyacrylonitrile/multiwall carbon nanotube composites

“…). Indeed, α relaxation is caused by the interaction between crystalline and amorphous phases, the π interaction in crystalline CNTs being much stronger than the dipole–dipole interaction of nitrile groups in PAN (see and the references therein). To identify the α transition, the imaginary part of electric modulus has been represented in Fig.…”