Cure Index for labeling curing potential of epoxy/LDH nanocomposites: A case study on nitrate anion intercalated Ni-Al-LDH

Abstract

Curing process of thermoset nanocomposites strongly depends on the nature and functionality of nanoparticles. In the present work, Ni-Al layered double hydroxide (LDH) was synthesized and intercalated with nitrate anion via solvothermal method to form Ni-Al-NO3 LDH and characterized by FTIR, X-ray diffraction (XRD) and TGA techniques. Characterization proved the synthesis of Ni-Al LDH intercalated with nitrate anion by d-spacing value of 0.76 nm. Epoxy nanocomposite containing 0.1 wt.% of the synthesized LDH was prepared and its curing potential was studied by nonisothermal differential scanning calorimetry (DSC). According to the results and qualitative evaluations made by the use of Cure Index (CI), epoxy nanocomposite containing Ni-Al-NO3 LDHs revealed Excellent cure thanks to the participation of nitrate anion in epoxide ring opening reaction. The anions attack to the carbon atom of epoxide rings and breaking down the CO band led to facilitation of the curing reaction and formation of a more condensed cross-linked network. It was recognized that the CI can be used in labeling epoxy/LDH nanocomposites for curing potential demonstration.