Thermal Stability of Imidazolium Modified Clay and Tgddm-based Epoxy Nanocomposites

High performance epoxy resin (tetra-glycidyl-4,4’diamino-diphenyl methane-TGDDM) is brittle and is sensitive to moisture absorption and thermooxidative effects. An approach to mitigate polymer sensitivity towards moisture and thermal effects is to add clay. The addition of clay to resin systems (e.g. diglycidyl ether bisphenol A-DGEBA) has often yielded an overall improvement in properties of the nanocomposite. In particular, clay filled polymer have been known for the improvements in mechanical, barrier, thermal stability, and flame retardant properties (1-2). These improvements are achieved by adding few wt% of alkyl ammonium exchanged clay to resin so as to decrease the clay hydrophilicity and enhance resin-clay affinity. However, alkyl ammonium ions typically used in modified clay start thermally decomposing at temperatures as low as 150 °C (3). This is a major concern because modified clay and the high performance epoxy resin are usually exposed to temperatures nearly 200C during curing. The degradation of alkyl ammonium ions from the modified clay can lead to tactoid morphology as opposed to dispersed morphology (4). Ionic liquids can be used instead of alkyl ammonium salts to improve the thermal stability of nanoclay and nanocomposites. The objective of the study is to evaluate the thermal stability of imidazolium ion exchanged clay & modified clay filled epoxy resin.