Fish DNA-modified clays: Towards highly flame retardant polymer nanocomposite with improved interfacial and mechanical performance

Deoxyribonucleic Acid (DNA) has been recently found to be an efficient renewable and environmentally-friendly flame retardant. In this work, for the first time, we have used waste DNA from fishing industry to modify clay structure in order to increase the clay interactions with epoxy resin and take benefit of its additional thermal property effect on thermo-physical properties of epoxy-clay nanocomposites. Intercalation of DNA within the clay layers was accomplished in a one-step approach confirmed by FT-IR, XPS, TGA, and XRD analyses, indicating that d-space of clay layers was expanded from similar to 1.2 nm for pristine clay to similar to 1.9 nm for clay modified with DNA (d-clay). Compared to epoxy nanocomposite containing 2.5% wt of Nanomer I. 28E organoclay (m-clay), it was found that at 2.5% wt d-clay loading, significant enhancements of similar to 14%, similar to 6% and similar to 26% in tensile strength, tensile modulus, and fracture toughness of epoxy nanocomposite can be achieved, respectively. Effect of DNA as clay modifier on thermal performance of epoxy nanocomposite containing 2.5% wt d-clay was evaluated using TGA and cone calorimetry analysis, revealing significant decreases of similar to 4000 kJ/m(2) and similar to 78 kW/m(2) in total heat release and peak of heat release rate, respectively, in comparison to that containing 2.5% wt of m-clay.