Dielectric analyzers, commercially

The higher optical transparency of these polymers is attributed to the presence of the pendant 4-trilluoro-methylphenyl substituents in the polymer backbone. The dielectric constant values were measured by the parallel plate capacitor method using a dielectric analyzer. These PAs showed lower dielectric constants, in the range of 3.40-3.51 (1 MHz), than commercial Nylatron (approximately 3.7 at 1 MHz). The low dielectric constant values of these new PAs are mainly due to the presence of bulky 4-trilluorometh-ylphenyl pendant groups. 

A method which circumvents many of the disadvantages of the transmission line and cavity perturbation technique was pioneered by Stuchley and Stuchley (1980). This technique calculates the dielectric parameters from the microwave characteristics of the reflected signal at the end of an open-ended coaxial line inserted into a sample to be measured. This technique has been commercialized by Hewlett Packard with their development of a user-friendly software package (Hewlett Packard 1991) to be used with their network analyzer (Hewlett Packard 1985). This technique is outstanding because of its simplicity of automated execution as well as the fact that it allows measurements to be made over the entire frequency spectrum from 0.3 MHz to 20 GHz. 

TABLE 6.3. A Selection of Commercially Available Analyzers" Used for Dielectric Analysis of Polymers... 

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