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There was a hope that highly reactive nanoparticles would strongly facilitate crosslinking in epoxy-amine systems. In this work, silica (SiO 2 ) nanoparticles are physically modified with poly(ethyleneimine) as surface modifier. The SiO 2 nanoparticles were synthesized and physically decorated with poly(ethyleneimine), then the untreated and surface-treated SiO 2 nanoparticles were analyzed by FTIR, TGA and SEM techniques. The results show that poly(ethyleneimine) hyperbranched molecule is successfully attached to the surface of SiO 2 nanoparticles enabling epoxy ring opening. Both untreated and modified particles are impregnated into an epoxy/amine system to fabricate nanocomposite coatings. The effect of the aforementioned SiO 2 nanoparticles on the curing behavior of the epoxy/amine system was investigated by means of dynamic DSC analysis. The results demonstrated that, while addition of untreated silica nanoparticles could not seriously curing reactions, the introduction of poly(ethyleneimine)-modified SiO 2 facilitated crosslinking of epoxy/amine system thanks to the abundance of amine reactive groups on the particle surface that gives worth to the poly(ethyleneimine)-modified SiO 2 nanoparticles as a promising nanomaterial for manufacturing highly-curable epoxy-based nanocomposite coatings. [ABSTRACT FROM AUTHOR]

• Synthesis and characetrization of Mg–Al–LDH intercalated with nitrate anion was discussed. • FTIR, TGA, and XRD analyses confirmed successful characetrization of Mg–Al–NO 3 –LDH. • DSC analyses and Cure Index together revealed Excellent cure for epoxy/Mg–Al–NO 3 nanocomposites. This paper focuses to provide information about the structure-property relationship in epoxy/LDH system by studying the curing characteristic of nanocomposite containing 0.1 wt.% of Mg–Al–NO 3 –LDH. For this purpose, Mg–Al–LDH intercalated with nitrate anion was synthesized using hydrothermal method. The formation of lamellar structure of LDH was confirmed by Fourier-transform infrared spectrophotometry (FTIR), X-ray diffractometry (XRD), and thermogravimetric analysis (TGA/DTG) analyses. Then, the role of synthesized LDH in curing reaction of epoxy was qualitatively evaluated by nonisothermal differential scanning calorimetry (DSC) performed at different heating rates via Cure Index (CI). From this point of view, the cure state of epoxy nanocomposite at heating rate of 2 °C/min was Poor , due to the vitrification of epoxy system before complete cure taking place in the system. By increasing the heating rates up to 5, 7 and then 10 °C/min, the mobility reactants was increased in the system, so that curing reaction was facilitated. Besides, nitrate anion taking part in epoxide ring opening reaction caused progress in crosslinking network formation, as evidenced by Excellent cure state. [ABSTRACT FROM AUTHOR]

• Synthesis and characetrization of Zn-Al LDH intercalated with carbonate anion was discussed. • FTIR, TGA, and XRD analyses confirmed successful characetrization of Zn-Al-CO 3 LDH. • DSC analyses and Cure Index together revealed Excellent cure for epoxy/Zn-Al-NO 3 nanocomposites at intermediate rates, but Poor at very low and very high rates. In this work, the curability of epoxy nanocomposite consisting of Zn-Al layered double hydroxide (LDH) intercalated with carbonate anion (CO 3) was studied via nonisothermal differential scanning calorimetry (DSC) by the aid of Cure Index (CI). The hydrothermal-assisted constant pH coprecipitation method was used in synthesis of lamellar LDH and the resulting structure was confirmed by FTIR, XRD and TGA/DTGA analyses. From the CI point of view, the cure state of epoxy/Zn-A-CO 3 -LDH nanocomposite was Poor at heating rates of 2 (low) and 10 (high) ºC/min. By contrast, crosslinking of epoxy resin was facilitated in the presence of Zn-Al-CO 3 -LDH at intermediate heating rates of 5 and 7 °C/min due to intensified ring opening reaction of epoxy under the Lewis acid effect of Zn metal, which changed the cure label of epoxy/Zn-Al-CO 3 -LDH nanocomposite from Poor to Excellent. [ABSTRACT FROM AUTHOR]

• Synthesis of Ni-Al LDH intercalated with nitrate anion, Ni-Al-NO 3 was reported. • Ni-Al-NO 3 LDH was characetrized with FTIR, TGA, and XRD analyses to probe into structural changes. • Epoxy/Ni-Al-NO 3 LDH nanocomposites underwent dynamic DSC at various heating rates. • Overall, Cure Index was Excellent for epoxy/Ni-Al-NO 3 nanocomposites irrespective of heating rate. 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-NO 3 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-NO 3 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 C O 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. [ABSTRACT FROM AUTHOR]

• Synthesized and characetrized Mg-Al LDH intercalated with cabonate anion, Mg-Al-CO 3 LDH. • Fully characetrized Mg-Al-CO 3 LDH with FTIR, TGA, and XRD analyses. • Epoxy/Mg-Al-CO 3 LDH nanocomposites underwent dynamic DSC at various heating rates. • Overall, Cure Index was Poor for epoxy/Mg-Al-CO 3 LDH nanocomposites irrespective of heating rate. Labeling epoxy/layered double hydroxide (LDH) nanocomposites for properties requires a priori curability estimation. The co-precipitation method was applied in synthesis of Mg-Zn-Al ternary LDH and intercalation with carbonate anion led to development of Mg-Zn-Al-CO 3 -LDH. The structure of developed ternary LDH was studied by XRD, FTIR and TGA/DTG analyses. Nonisothermal differential scanning calorimetry (DSC) at heating rates of 2, 5, 7 and 10 °C/min was used to evaluate the curing potential of low-filled epoxy/LDH nanocomposite by labeling them for curability. It was unraveled by the use of Cure Index that even by using well-synthesized Mg-Zn-Al-CO 3 -LDH ternary structure the epoxy curing was hindered, underlining the importance of curability estimation before dealing with properties of epoxy/LDH systems. It can be concluded by accepting Poor label for the studied system that although carbonate ion deposition in between galleries enlarged interlayer space it inevitably confined collision between epoxy and amine curing precursor. This negative effect was signaled by a significant fall in heat release amount of nanocomposites sample compared to the neat epoxy irrespective of heating history. [ABSTRACT FROM AUTHOR]

• Synthesized Mg-Al LDH intercalated with carnonate ions. • Fully characetrized Mg-Al-CO 3 LDH with FTIR, TGA, and XRD analyses. • Epoxy/ Mg-Al-CO 3 LDH nanocomposites underwent nonisothermal DSC at various heating rates. • Cure Index revealed Poor cure unconditionally for epoxy/Mg-Al-CO 3 LDH nanocomposites due to cabonate ion interation with amine curing agent. Properties of epoxy/layered double hydroxide (LDH) nanocomposites depend on the extent to which epoxy has tendency towards metal cations as well as intercalating anionic minerals used in LDH synthesis. In this work, Mg-Al LDH was synthesized and intercalated with carbonate (CO 3), then characterized with FTIR, X-ray diffractometry (XRD), and TGA/DTG analyses. The potential of the synthesized Mg-Al-CO 3 LDHs for opening epoxy ring was examined by preparing epoxy nanocomposites containing 0.1 wt.% of LDHs. Differential scanning calorimetry (DSC) under nonisothermal scans at different heating rates of 2, 5, 7 and 10 °C/min was indicative of unconditional Poor cured epoxy nanocomposites, as recognized qualitatively by the use of Cure Index , which was attributed to hindered crosslinking caused by carbonate groups. [ABSTRACT FROM AUTHOR]