Diglycidyl ether of Bisphenol A (DGEBA) based SC-15 epoxy resin was modified with three different commercially available montmorillonite (MMT) nanoclay: Nanomer I.28E and Cloisite 10A and 30B. Cure behavior of nanocomposites was studied using a variety of techniques. Primary focus of this study was to investigate influence of different surface modifications of MMT nanoclay on rheological properties and cure behavior of SC-15 epoxy resin. By adding MMT to SC-15 epoxy resin, chemistry of the epoxy is altered leading to changes in rheological properties and ultimately enthalpy and activation energy of reactions. Addition of Nanomer I.28E delayed gelation, while Cloisite 10A and 30B accelerated gelation, regardless of the curing temperature. Activation energy of reaction was lower with the addition of Nanomer I.28E and Cloisite 10A and higher for Cloisite 30B compared to neat SC-15 epoxy composite. 1. Introduction Thermosetting epoxy resins are widely used across many industries in a variety of applications such as in paint and coating industries, adhesives, and as matrices for composite laminates due to exceptional properties [1–4]. These properties are further enhanced by modifying resins with small amounts of fillers such as nanoparticles. In this process, chemistry of the polymer systems is altered and consequently affects their processing. Properties of most polymeric composites depend on processing parameters including curing temperature and time to a great extent, leading to formation of network of polymer chains. However, in reinforced polymer composites, properties are mostly dictated by the interfacial chemistry and subsequent interaction between filler materials and polymers molecules along with the aforementioned factors. Among many commercially available nanoparticles used as fillers in epoxy resins, nanoclay stands out as the one with an ability to improve mechanical and thermal properties [4–6]. MMT also exhibits good barrier properties against moisture and volatiles during decomposition based on their unique morphology [7, 8]. One such nanoclay is naturally occurring 2？:？1 phyllosilicate montmorillonite clay which in the natural form is hydrophilic and incompatible with most polymers. Hence, surface of most commercially available nanoclay used as fillers is modified using organic modifiers to overcome these challenges leading to the formation of miscible solutions [9, 10]. Surface modifications also help to reduce tendency of clay agglomeration during dispersion by reducing interlayer attractive forces between the platelets thereby enhancing
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