Yoshihiko Hirano

Preparation and properties of epoxy-organically modified layered silicate nanocomposites

Epoxy-silicate nanocomposites were prepared by dispersing synthetic layered silicates modified with alkylammonium ions. In the dispersing process, the organically modified layered silicates were mixed in epoxy resin with shearing, and aggregations of the silicates were removed by centrifugal separation after mixing epoxy resin and silicates. Micrographs taken by transmission electron microscopy (TEM) indicate that the nanocomposites have a mixed morphology including both parallel silicate layers (0.1-0.5 /spl mu/m, 5-15 layers) and exfoliated silicate layers (nano-scale dispersion) area. In terms of thermal resistance properties, the glass transition temperature (T/sub g/) of the nanocomposite was shifted to a higher temperature (/spl Delta/20/spl deg/C) than pure epoxy. Furthermore, dispersion of modified silicate prevented relative permittivity (/spl epsiv//sub r/) and dielectric loss (tan/spl delta/) from increasing at a high temperature above the glass transition temperature.

Digest report on the investigation committee on surface properties and long-term performance of polymeric insulating materials for outdoor use

Application of polymeric insulators has been expanded in the filed of power supply and distribution system all over the world. Compared to porcelain insulators, however, polymeric insulators have been demanded to solve the challenging subjects on a long-term reliability and diagnosis techniques in the real application field.