FILM FORMATION BEHAVIOR OF BLENDS OF CONDUCTING- INSULATING EPOXY RESINS DURING CATHODIC ELECTRODEPOSITION

摘要

Different blends of a low-EEW (LEEWA) and a high-EEW epoxy-amine adduct (HEEWA) were prepared and electro-deposited. The LEEWA and HEEWA behaved conductive and insulative, respectively. It was found that the electrical conductivity behavior of the mixed films during the electro-deposition can be explained by a suitable percolation model. The experimental results showed a good agreement with the random resistor network model of Miller & Abrahams. Based on the above discussion the mean size of the conducting paths in the deposited film was calculated as 10 times of the mean size of the conductive resin particles. It was found that the critical exponent of conductivity for the percolating cluster is less than that of a classical three dimensional lattice. This discrepancy was explained in terms of the disconnecting effect of the gas bubbles on the percolating cluster.