Hysteresis in the relation between moisture uptake and electrical conductivity in neat epoxy
Language
en
Article de revue
This item was published in
Polymer Degradation and Stability. 2017, vol. 141, p. 54-57
Elsevier
English Abstract
Monitoring changes in electrical conductivity is a simple way to assess the water uptake from environmental moisture in polymers. However, the relation between water uptake and changes in conductivity is not fully understood. ...Read more >
Monitoring changes in electrical conductivity is a simple way to assess the water uptake from environmental moisture in polymers. However, the relation between water uptake and changes in conductivity is not fully understood. We monitored changes in the electrical volume conductivity of an anhydride-cured epoxy polymer during moisture sorption-desorption experiments. Gravimetric analysis showed that the polymer exhibits a two-stage sorption behavior resulting from the competition between diffusive and reactive mechanisms. As expected, the macroscopic electrical conductivity increases with the diffusion of water. However, our most surprising observation was severe hysteresis in the relation between water uptake and electrical conductivity during the sorption and desorption experiments. This indicates that change in the electrical conductivity depends on both the water uptake and the competition between the diffusive and reactive mechanisms. We studied samples with various thicknesses to determine the relative effects of the diffusive and reactive mechanisms. This is an important observation as it means that general electrical monitoring techniques should be used cautiously when it comes to measuring the moisture content of polymer or polymer-based composite samples.Read less <
English Keywords
Epoxy
Moisture sorption
Hydrolysis
Electrical properties
Diffusion
Origin
Hal imported