Influence of thermal degradation of synthetic polymers (EPR, EPDM) on electrical characteristics

Electrical characteristics: dielectric constant, dielectric loss and volume resistivity were measured and correlated with structural changes induced by heating in water at three temperatures (40/spl deg/, 60/spl deg/ and 80/spl deg/C). IR and electrical determinations prove that oxygenated products decrease the material quality by worsening useful parameters. Degradation effects represent the contribution of products like alcohols and ketones to electrical behaviour of elastomers. These compounds act as dipoles, whose concentrations influence the electrical properties. The damage product level depends on the formation route. During the first stage of ageing the measured characteristics increased. After a long heating time, chemical attack tends to diminish the insulation behaviour of studied elastomers.