Synthesis and characterization of organosoluble, thermoplastic elastomer/clay nanocomposites

Abstract

AbstractWe synthesized organosoluble, thermoplastic elastomer/clay nanocomposites by making a jelly like solution of ethylene vinyl acetate containing 28% vinyl acetate (EVA‐28) and blending it with organomodified montmorillonite. Sodium montmorillonite (Na+‐MMT) was made organophilic by the intercalation of dodecyl ammonium ions. X‐ray diffraction patterns of Na+‐MMT and its corresponding organomodified dodecyl ammonium ion intercalated montmorillonite (12Me‐MMT) showed an increase in the interlayer spacing from 11.94 to 15.78 Å. However, X‐ray diffraction patterns of the thermoplastic elastomer and its hybrids with organomodified clay contents up to 6 wt % exhibited the disappearance of basal reflection peaks within an angle range of 3–10°, supporting the formation of a delaminated configuration. A hybrid containing 8 wt % 12Me‐MMT revealed a small hump within an angle range of 5–6° because of the aggregation of silicate layers in the EVA‐28 matrix. A transmission electron microscopy image of the same hybrid showed 3–5‐nm 12Me‐MMT particles dispersed in the thermoplastic elastomer matrix; that is, it led to the formation of nanocomposites or molecular‐level composites with a delaminated configuration. The formation of nanocomposites was reflected through the unexpected improvement of thermal and mechanical properties; for example, the tensile strength of a nanocomposite containing only 4 wt % organophilic clay was doubled in comparison with that of pure EVA‐28, and the thermal stability of the same nanocomposite was higher by about 34 °C. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2065–2072, 2002