Continuous dielectric measurement of polymerizing systems

Abstract Frequency-dependent dielectric measurement techniques made over many decades, Hz to MHz, can provide a convenient automated technique for characterizing the polymerization reaction in thermoset polymers. The frequency dependence of the complex permittivity is used to simultaneously separate and measure the relaxation and diffusion parameters governing dipolar and ionic mobility. The quantitative relationship of the viscosity and degree of cure during polymerization to the ionic and dipolar mobility is discussed and analyzed in relation to the gel point and the Vogel-Tammann-Fulcher (VTF) equation. An interdigitated planer electrode permits measurement of the variation in the rate of polymerization in situ at various positions in the system due to exothermic and heat transfer effects.