Solvent effects, carbon black dispersions

Solvent effects on Monarch 1100 dispersions were also investigated. Table in shows the results when 0.1 wt% solids were mixed with water, toluene and hexachlorobutadiene under identical conditions of ultrasound treatment. It is evident that toluene is not a good medium into which any of the Monarch type san iles should be dispersed. Furthermore, by con aring with Table II data, water has been siqierceded by the chlorinated organic as the best of the solvents evaluated to achieve carbon black size reduction. It is not possible to explain die observed trend of solvent effects on particle size reduction by shear or sonic... 

In order to understand the phenomena behind resistance variations in the conductive polymer composites (CPCs) due to solvent diffiision. Feller et al. [71] have performed sorption exjjeriments with poly (ethylene-co-ethyl acrylate)-carbon black (EEA-CB) and EEA films in the presence of toluene. One main point here was to determine the influence of CB in the diffiision process. The first results showed that, whichever polymer was used, the diffiision coefificiem increased with toluene activity, which indicated plasticization of the material by the solvent. However, it was interesting to note that the plasticization phenomenon was reduced when fillers were introduced into the polymer matrix. It also appeared that the toluene diflfiisivity was about twofold lower in EEA-CB than in EEA, which was certainly due to a hindrance effect of the carbon black particles. In other words, the decrease in toluene solubility was the result of a tortuosity effect due to the morphology of CPC with a dispersion of CB particles, which acted as barrier components and increased the path for toluene molecules inside the composite. 

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