In this work, graphene oxide (GO) nanoplatelets were chemically functionalized with starch biopolymer to proceed with the epoxy ring opening, which is believed to be predominantly controlled by diffusion. The product was a high-performance epoxy nanocomposite for coating applications. Successful attachment of the starch to the GO surface was approved by Fourier transform infrared spectroscopy and thermogravimetric analysis. Cure behavior of neat epoxy and its nanocomposites containing pristine and starch-modified GO was studied by differential scanning calorimetry (DSC) varying the heating rate to track and compare variations in heat of cure and maximum cure temperature of samples. Eventually, the state of brittleness of specimens was assessed; both mechanistically and microscopically. The results suggest that the huge starch molecules attached to the surface of GO could efficiently contribute to the crosslinking reactions through exfoliation of GO interlayer distance leading to a significant rise in the value of heat of cure of epoxy/amine system from 448.3 mJ/mg for neat epoxy to 515.6 mJ/mg for epoxy/GO and 468.1 mJ/mg for epoxy/GO-St at low heating rate. Epoxy nanocomposites showing acceptable curing potential and fracture resistance are appeared appropriate for coating application
Development and curing potential of epoxy/starch-functionalized graphene oxide nanocomposite coatings
Rallini, Marco;Puglia, Debora
2018
Abstract
In this work, graphene oxide (GO) nanoplatelets were chemically functionalized with starch biopolymer to proceed with the epoxy ring opening, which is believed to be predominantly controlled by diffusion. The product was a high-performance epoxy nanocomposite for coating applications. Successful attachment of the starch to the GO surface was approved by Fourier transform infrared spectroscopy and thermogravimetric analysis. Cure behavior of neat epoxy and its nanocomposites containing pristine and starch-modified GO was studied by differential scanning calorimetry (DSC) varying the heating rate to track and compare variations in heat of cure and maximum cure temperature of samples. Eventually, the state of brittleness of specimens was assessed; both mechanistically and microscopically. The results suggest that the huge starch molecules attached to the surface of GO could efficiently contribute to the crosslinking reactions through exfoliation of GO interlayer distance leading to a significant rise in the value of heat of cure of epoxy/amine system from 448.3 mJ/mg for neat epoxy to 515.6 mJ/mg for epoxy/GO and 468.1 mJ/mg for epoxy/GO-St at low heating rate. Epoxy nanocomposites showing acceptable curing potential and fracture resistance are appeared appropriate for coating applicationI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
