Abstract

The novelty of this paper is to quantify the contribution of micro mechanisms caused the changes in fracture behavior of a model system epoxy resin by introduction of intercalated nano clay. To achieve this aim, a combination of fracture toughness measurements, electron and optical microscopy assessments and analytical models have been used. The results obtained indicated that addition of intercalated nano clay increased fracture toughness of the epoxy resin, although the increases in toughness were modest. Examination of fracture surfaces and subsurface damage revealed the presence of crack deflection, particle bridging and crack branching/microcracking mechanisms. Analysis of the micromechanical models for these toughening mechanisms suggested that crack branching contributes the most to the increase in toughness. In addition in the present study, the possible additive effects of crack path deflection, crack wake bridging, and crack branching and microcracking have been observed as the sources of modest improvements in toughness for these intercalated clay-filled epoxies.

Keywords: Modeling; Toughening mechanism; Intercalation;Nano clay; Epoxy

Abbreviations: TEM: Transmission Electron Microscope; DSC: Differential Scanning Calorimetry; SEM: Scanning Electron Microscope; TOM: Transmission Optical Microscopy