Effect of Clay Surfactant Type and Clay Content on the Rheology and Morphology of Uncured Fluoroelastomer/Clay Nanocomposites Prepared by Melt-Mixing

Fluoroelastomer/clay composites were prepared by melt mixing in an internal mixer using Cloisite(R) Nanoclays: NA, 15A, 20A, 30B, and 93A at three different concentrations viz. 2.5, 5.0, and 10.0 phr. Rheology, X-ray diffraction (XRD), and transmission electron microscopy (TEM) were used to characterize the composites prepared. Dynamic rheological measurements showed significant increase in storage moduli (G) in the terminal frequency region for the uncured composites prepared from Cloisite(R) 15A and 20A. At higher frequencies, organically modified nanoclays plasticize the polymer matrix leading to lower modulus values. Using all three characterization techniques, Cloisite(R) 15A and 20A were shown to have intercalated structure in the fluoroelastomer matrix, whereas other nanoclays were shown to have inferior dispersion. The storage modulus increases proportionally with increase in the clay loading and no clay aggregation was observed at higher loadings. (C) 2009 Wiley Periodicals, Inc. Appl Polym Sci 112: 3597-3604, 2009