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Thermal aging of undoped polyaniline: Effect of chemical degradation on electrical properties
Author(s) -
Kieffel Yannick,
Travers Jean Pierre,
Ermolieff Anne,
Rouchon Denis
Publication year - 2002
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.10981
Subject(s) - polyaniline , polymer , x ray photoelectron spectroscopy , materials science , degradation (telecommunications) , fourier transform infrared spectroscopy , imine , polymer degradation , polymer chemistry , chemical engineering , radical , intrinsic viscosity , photochemistry , chemistry , composite material , organic chemistry , polymerization , catalysis , telecommunications , computer science , engineering
Aging experiments, with a special emphasis on the atmosphere effect, have been carried out on undoped polyaniline, in its half‐oxidized state, namely emeraldine base (EB). The polymer has been aged under vacuum and in air atmosphere. The chemical degradation has been analyzed by several complementary techniques such as viscosity measurements, FTIR, XPS, and UV‐Vis‐nIR spectroscopy. We show that emeraldine base exhibits two different degradation mechanisms. The first one is intrinsic to the polymer and occurs independently on aging conditions (vacuum or air). It consists of crosslinking via tertiary amine groups created from imine nitrogen via double‐bond breaking. The second mechanism is extrinsic and occurs concomitantly with the first one upon aging in air. It consists of oxygen incorporation in a form of carbonyl groups and chain scission. Both degradation pathways result in a decrease of the electrical conductivity of the polymer due to the lowering of the average conjugation length. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 395–404, 2002