IN-LINE DIELECTRIC MONITORING DURING EXTRUSION OF FILLED POLYMERS

摘要

Dielectric measurements were made on clay filled polyethylene-ethyl vinyl acetate (EVA) copolymer nanocomposites during processing by extrusion. The results show that, at processing temperatures, composites containing chemically treated clays display significant dielectric dispersions. The addition of natural clay to the EVA copolymer increased the dielectric constant (relative permittivity) above that of the EVA copolymer but did not increase the conductivity or cause any dispersion. The chemically treated clays, which are known to exfoliate when compounded with EVA copolymer, gave substantially higher relative permitivity and conductivity having distinct variations with frequency consistent with dielectric relaxations at frequencies below 3000 Hz. One clay treatment gave a larger dielectric dispersion than the other.