Effect of Post Curing Temperature on Viscoelastic and Flexural Properties of Epoxy/Alumina Polymer Nanocomposites

In the present work, effect of post curing temperature on viscoelastic and flexural properties of epoxy/alumina polymer nanocomposite was evaluated in order to optimize the post curing temperature. Polymer nanocomposites (PNC) containing of 0.5, 1 and 1.5 wt.% of rod shape alumina nanoparticles were prepared by in-situ polymerization technique. Good dispersion of nanoparticles in epoxy matrix was observed through transmission electron micrographs of nanocomposites. The curing reaction of the epoxy and nanocomposites was analyzed through Differential Scanning Calorimetry (DSC) for temperature varying from 25 °C to 200 °C. Temperatures 80 °C, 100 °C, 120 °C and 150 °C were selected for post curing on the basis of DSC thermographs. Dynamic mechanical analysis (DMA) tests were performed to determine the viscoelastic properties and three point bend flexural tests were conducted to evaluate the flexural properties of PNC. The results indicated that the post curing at a temperature below the glass transition temperature of epoxy enhanced the viscoelastic and flexural properties of PNC's and post curing temperature above the glass transition temperature of epoxy had a detrimental effect on the properties for both neat epoxy as well as nanocomposites. As the post curing temperature was increased the glass transition temperature increases for both the neat epoxy and nanocomposites, however the increment in glass transition temperature of PNC was more in comparison to that of neat epoxy. Flexural modulus and strength of epoxy and PNC decreased with the increase in post cure temperature.