Dependence of Electrical Properties on Moisture

Since the electroconductivity of pure water is by several orders of m itude hi er than those of polymers, even smaU amounts of moisture markedly reduce electrical insulation properties of foams. For this reason, measuren nt of dielectric properties is a precise, rapid and non-destructive method of monitoring the kinetics and level of moisture absorption. Thus, the establishment of correlations between dielectric properties and the hygroscopicity of plastic foams makes it possible to solve two practical problems how moisture affects dielectric properties and how to determine non-electrical properties by electrical measurements [Pg.54]

The calculation of the effect of a liquid on the dielectric properties of foams requires repre ntation of the structure as a polymeric matrix with two-layer ellipsoidal inclusions, one of the layers being a film of sorbed moisture. [Pg.54]

The expression for the calculation of dielectric properties of heterogeneous media containing n components was derived by Vanin [Pg.54]

For a three-component system (plastic foam) Eq. (46) may be written as [Pg.54]

Shutov and Chaikin showed that for rigid PUR foams [Pg.54]

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