Fracture-mechanical properties of tailored epoxy nanocomposites at elevated temperatures

An investigation was conducted to assess the influence of hybridized block-copolymer (BCP) and core-shell rubber (CSR) particles on the tensile properties, fracture mechanical properties, and toughening mechanisms of a high strength epoxy/anhydride system at elevated temperatures (80 degrees C). Utilizing standard tensile and compact tension (CT) specimens, substantial increases in fracture energy were observed for specimens enhanced with nanoparticles-831% for the 4 wt.% BCP-toughened system and 600% for the 12 wt.% CSR-toughened system. Field emission gun-scanning electron microscope imaging indicated that the inclusion of BCP and CSR significantly altered fracture surface morphologies, consistent with the improved mechanical properties. Glass transition temperature (T-g) determined through dynamic mechanical analysis-were not significantly influenced by additive inclusion, presenting a similar to 1 degrees C decrease for BCP and similar to 3 degrees C increase for CSR toughened systems relative to the unaltered matrix. Toughening mechanisms induced by the BCP and CSR particles were identified as (a) localized enhanced plastic shear-band yielding around the particles and (b) cavitation of the particles followed by enhanced plastic void growth in the epoxy matrix. Outcomes from this study highlight the role of BCP and CSR particles in the toughening of epoxy/anhydride systems and provide a comprehensive assessment of their influence on mechanical characteristics at high temperatures.