Self-similarity of dielectric relaxation and conductivity in cross-linking systems

Dielectric measurements of a polymerizing amine/epoxy system were carried out in the frequency interval 10³--10¹⁰ Hz. The vitrification of the system due to the increase of connectivity was analyzed by measuring the change of the shape parameters of the main relaxation, m and n, during the reaction; the sol-gel transition was also studied by simultaneously measuring the dc conductivity. Results indicate that the relaxation and conductivity behavior of the system can be satisfactorily described under theories based on a percolation approach. {} 1996 The American Physical Society.