Suspensions of epoxy with 10% by weight of organomodified montmorillonite clay [Cloisite 30B], prepared by two different methods, viz. intensive batch mixing and sonication, were investigated. The characterization of linear viscoelastic material functions of the suspension using small-amplitude oscillatory shear during processing enabled the assessments of the dispersion capabilities of the two mixing methods. Thermal imaging was used to monitor the temperature distributions generated during mixing. Sonication was determined to be more effective in the dispersion of the clay into the epoxy resin than the intensive batch mixing process, as revealed by the significant increase of the dynamic properties upon sonication, which suggested that some degree of intercalation and exfoliation had taken place during sonication. The use of the linear viscoelastic material functions thus provided a relatively easy to implement method for the analysis of the dispersion effectiveness of the different processing methods and operating conditions. (c) 2012 Wiley Periodicals, Inc.