Curing epoxy with electrochemically synthesized Mn_xFe_3-xO₄ magnetic nanoparticles

Typically, surface functionalization of nanoparticles was practised as a useful strategy to enhance curing of thermoset nanocomposites after gelation takes place. By contrast, modification of bulk composition of nanoparticles for crosslinking facilitation was not reported. In this work, manganese (Mn)-doped Fe₃O₄ magnetic nanoparticles were synthesized via cathodic electrodeposition and characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), dispersive X-ray spectrometry (EDAX), and vibrating sample magnetometry (VSM). Low-filled epoxy nanocomposites containing Fe₃O₄ and Mn²⁺-doped Fe₃O₄ were then prepared to study the effect of cationic exchange between the first main transition series of periodic table of elements (Fe²⁺ cations were replaced by Mn²⁺ cations in Fe₃O₄) on epoxy curing reaction with a linear aliphatic amine. Nonisothermal differential scanning calorimetry (DSC) was used to evaluate epoxy crosslinking. Cure Index demonstrated that Mn²⁺ cations played the role of catalyst in epoxy/amine curing reaction, so that a shift from Poor to Good and Excellent cure was detected.