Effect of Ethylene Glycidyl Methacrylate Compatibilizer on the Structure and Mechanical Properties of Clay Nanocomposites Modified with Ethylene Vinyl Acetate Copolymer B. R. Guduri, 1,2 A. S. Luyt 1 1 Department of Chemistry, University of the Free State (Qwaqwa Campus), Private Bag X13, Phuthaditjhaba 9866, South Africa 2 Materials Science and Manufacturing, Council for Scientific and Industrial Research, P. O. Box 395, Pretoria 0001, South Africa Received 13 July 2006; accepted 4 September 2006 DOI 10.1002/app.25512 Published online in Wiley InterScience (www.interscience.wiley.com). ABSTRACT: The structure and mechanical properties of clay modified with ethylene vinyl acetate copolymer in the presence of ethylene glycidyl methacrylate (EGMA) were investigated as a function of compatibilizer and clay contents. The structure and properties were determined by X-ray diffraction, transmission electron microscopy, differential scanning calorimetry, and thermogravimetric analysis (TGA). The presence of EGMA caused strong exfoliation of the clay in the polymer matrix, although at higher clay contents, some clay layers still existed. The more effective exfoliation, however, did not seem to substantially influence the tensile properties of the nano- composites because the EGMA itself had a much stronger influence, which overshadowed any possible influence that the EGMA–clay interaction may have had on these properties. The thermal stability of the nanocomposites (as studied by TGA) improved in the presence of EGMA. Ó 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 4095–4101, 2007 Key words: composites; mechanical properties; morpho- logy; nanolayers; organoclay INTRODUCTION Nanocomposites are a new class of composites deri- ved from ultrafine inorganic particles, with dimen- sions typically in the range 1–1000 nm, that are homogeneously dispersed in the polymer matrix. 1 Recently, these kinds of materials have received the attention of government, academic, and industrial researchers because of their outstanding properties. These polymer layered silicate nanocomposites can attain a certain degree of stiffness, strength, and barrier properties with a far lower ceramic content than comparable glass or general inorganic-reinforced polymers. 2 Polymer–clay nanocomposites were first reported in the literature as early as 1961, when Blumstein 3 demonstrated the polymerization of vinyl monomers intercalated into montmorillonite clay. Different methods for preparing polymer–clay nano- composites were developed by several groups. 4–6 In general, these methods achieve molecular-level incorporation of the layered silicate (e.g., montmoril- lonite) into the polymer by the addition of a modified silicate during the polymerization (in situ method) to either the solvent-swollen polymer or the polymer melt. 7–9 There are four methods for making nanocom- posites: exfoliation–adsorption, in situ intercalative polymerization, melt intercalation, and template syn- thesis. 10 Melt intercalation of polymers has proven to be a more efficient and environmentally benign al- ternative to other methods. 11 When polymer–clay nanocomposites are prepared via either in situ poly- merization or direct intercalation, a very specific temperature is needed in the processing. 12,13 If the processing temperature is higher than the thermal stability of the organic modifier, decomposition of the organic treatment is meaningful in the process of making polymer–clay nanocomposites. 14–16 Direct dispersion of the organoclay in the molten polymer with an extruder is the most appropriate technique for the industrial preparation of polymer layered silicate nanocomposites. Two classes are universally accepted: intercalated nanocomposites, where the polymer chains are intercalated in the gal- leries, and delaminated or exfoliated nanocomposites, where the delaminated silicate is uniformly dis- persed in the matrix. The aspect ratio and dispersion Correspondence to: A. S. Luyt (luytas@qwa.uovs.ac.za). Contract grant sponsor: National Research Foundation in South Africa; contract grant number: GUN 2050677. Contract grant sponsor: University of the Free State. Journal of Applied Polymer Science, Vol. 103, 4095–4101 (2007) V V C 2006 Wiley Periodicals, Inc.