Filler systems silane coupling agents, chemistry

Electrical properties of filled resin systems are also improved by filler treatment. Filler particles are naturally hydrophilic via their metal hydroxide surfaces, and the particles naturally seek to agglomerate with each other, and so transport electrical charges through resin composite. Treatment with silane-coupling agent alters the chemistry of the filler surface, allow better dispersion of the filler throughout the resin matrix, and imparts improved electrical properties to the composite. Table 15.13 indicates the improved electrical properties of a quartz-fiUed epoxy resin system with 0.3% silane admixed into the formulation. Improved insulation values, including reduced dielectric constant and reduced dissipation factor, are also denoted. 

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