Imidazole-functionalized nitrogen-rich Mg-Al-CO3 layered double hydroxide for developing highly crosslinkable epoxy with high thermal and mechanical properties

Abstract

Ionic liquid-based N-octadecyl-N'-octadecyl imidazolium iodide functionalized layered double hydroxide (LDH-IM) was synthesized for manufacturing high-performance epoxy nanocomposites. Nonisothermal differential scanning calorimetry (DSC) was performed to study cure kinetics of epoxy reinforced قث with LDH and LDH-IM. Incorporation of Mg-Al-CO3 LDH into epoxy hindered the curing reaction, as detected by dimensionless Cure Index (CI). By contrast, epoxy/LDH-IM cured Good and Excellent due to imidazolium ionic liquid. Higher activation energy for completely cured epoxy/LDH-IM nanocomposite was obtained compared to epoxy and epoxy/LDH nanocomposites. The curing reaction rate was obtained by calculation of the orders of instantaneous autocatalytic and non-catalytic reactions, and optimal kinetic parameters based on isoconversional methods were in good agreement with experimental cure reaction rates. Lower value of Tg for epoxy/LDH nanocomposite compared to the neat epoxy signified weak interactions between Mg-Al-CO3-LDH and epoxy matrix, while a higher Tg was obtained for epoxy/LDH-IM. Network degradation kinetics of the samples was also investigated. The higher decomposition activation energy for epoxy/LDH-IM approved strong interfacial adhesion in the assigned system. The highly reactive nature of the developed LDH-IM gives reason for its usage for developing highly curable epoxy with high thermal and mechanical properties.