Development of Mg-Zn-Al-CO3 ternary LDH and its curability in epoxy/amine system

Karami, Zohre; Jouyandeh, Maryam; Ali, Jagar A.; Ganjali, Mohammad Reza; Aghazadeh, Mustafa; Maadani, Mona; Rallini, Marco; Luzi, Francesca; Torre, Luigi; Puglia, Debora; Saeb, Mohammad Reza

doi:10.1016/j.porgcoat.2019.105264

Cited by 37 publications

(28 citation statements)

References 33 publications

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“…The α-time curves in Figure 5 indicate that cure conversion progress in all samples follows a similar trend to that of the reference sample. The results give an image of the dominant mechanism of reaction which appears to be autocatalytic due to the sigmoidal shape of the curve [39]. The retardation in the preliminary phase of the cure is explained by increased viscosity as a result of nanoadditives, which hinders the accessibility of cure species [40].…”

Section: Quantitative Cure Analysismentioning

confidence: 98%

Curing Kinetics and Thermal Stability of Epoxy Composites Containing Newly Obtained Nano-Scale Aluminum Hypophosphite (AlPO2)

et al. 2020

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For the first time, nano-scale aluminum hypophosphite (AlPO2) was simply obtained in a two-step milling process and applied in preparation of epoxy nanocomposites varying concentration (0.1, 0.3, and 0.5 wt.% based on resin weight). Studying the cure kinetics and thermal stability of these nanocomposites would pave the way toward the design of high-performance nanocomposites for special applications. Scanning electron microscopy (SEM) and transmittance electron microscopy (TEM) revealed AlPO2 particles having domains less than 60 nm with high potential for agglomeration. Excellent (at heating rate of 5 °C/min) and Good (at heating rates of 10, 15 and 20 °C/min) cure states were detected for nanocomposites under nonisothermal differential scanning calorimetry (DSC). While the dimensionless curing temperature interval (ΔT*) was almost equal for epoxy/AlPO2 nanocomposites, dimensionless heat release (ΔH*) changed by densification of polymeric network. Quantitative cure analysis based on isoconversional Friedman and Kissinger methods gave rise to the kinetic parameters such as activation energy and the order of reaction as well as frequency factor. Variation of glass transition temperature (Tg) was monitored to explain the molecular interaction in the system, where Tg increased from 73.2 °C for neat epoxy to just 79.5 °C for the system containing 0.1 wt.% AlPO2. Moreover, thermogravimetric analysis (TGA) showed that nanocomposites were thermally stable.

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Section: Quantitative Cure Analysismentioning

confidence: 98%

Curing Kinetics and Thermal Stability of Epoxy Composites Containing Newly Obtained Nano-Scale Aluminum Hypophosphite (AlPO2)

et al. 2020

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“…For both samples, the IR band at about 3542 cm −1 corresponds to the O–H stretching vibration of the interlayer water molecules and the –OH groups in the LDH layers [ 24 , 25 ]. The weak band observed at 1640 cm −1 can be attributed to the bending vibration of H-O of the interlayer water [ 26 , 27 ]. Moreover, the characteristic bands of the carbonate ion are present at 1456 cm −1 , related to carbonated hydroxyapatite.…”

Section: Resultsmentioning

confidence: 99%

Kinetics of Cross-Linking Reaction of Epoxy Resin with Hydroxyapatite-Functionalized Layered Double Hydroxides

et al. 2020

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The cure kinetics analysis of thermoset polymer composites gives useful information about their properties. In this work, two types of layered double hydroxide (LDH) consisting of Mg2+ and Zn2+ as divalent metal ions and CO32− as an anion intercalating agent were synthesized and functionalized with hydroxyapatite (HA) to make a potential thermal resistant nanocomposite. The curing potential of the synthesized nanoplatelets in the epoxy resin was then studied, both qualitatively and quantitatively, in terms of the Cure Index as well as using isoconversional methods, working on the basis of nonisothermal differential scanning calorimetry (DSC) data. Fourier transform infrared spectroscopy (FTIR) was used along with X-ray diffraction (XRD) and thermogravimetric analysis (TGA) to characterize the obtained LDH structures. The FTIR band at 3542 cm−1 corresponded to the O–H stretching vibration of the interlayer water molecules, while the weak band observed at 1640 cm−1 was attributed to the bending vibration of the H–O of the interlayer water. The characteristic band of carbonated hydroxyapatite was observed at 1456 cm−1. In the XRD patterns, the well-defined (00l) reflections, i.e., (003), (006), and (110), supported LDH basal reflections. Nanocomposites prepared at 0.1 wt % were examined for curing potential by the Cure Index as a qualitative criterion that elucidated a Poor cure state for epoxy/LDH nanocomposites. Moreover, the curing kinetics parameters including the activation energy (Eα), reaction order, and the frequency factor were computed using the Friedman and Kissinger–Akahira–Sunose (KAS) isoconversional methods. The evolution of Eα confirmed the inhibitory role of the LDH in the crosslinking reactions. The average value of Eα for the neat epoxy was 54.37 kJ/mol based on the KAS method, whereas the average values were 59.94 and 59.05 kJ/mol for the epoxy containing Zn-Al-CO3-HA and Mg Zn-Al-CO3-HA, respectively. Overall, it was concluded that the developed LDH structures hindered the epoxy curing reactions.

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“…Qualitative cure analysis of silicone/HNTs nanocomposites was evaluated in term of the Cure Index ( CI ) gauge. [ 21 ] Dimensionless parameters of Δ H *, Δ T *, and the CI for the silicone nanocomposites consisted of pristine and functionalized HNTs were calculated by using the following equations [ 39 ] :

normalΔ H^{*} = \frac{normalΔ H_{C}}{normalΔ H_{Re f}}

normalΔ T^{*} = \frac{normalΔ T_{C}}{normalΔ T_{Re f}}

italicCI = normalΔ H^{*} \times normalΔ T^{*}

…”

Section: Cure Analysismentioning

confidence: 99%

“…[ 21‐23 ] Determination of the CI based on nonisothermal differential scanning calorimetry (DSC) data enables one to roughly estimate the quality of crosslinking by tagging the thermoset composite as Poor , Good , and Excellent cured networks. [ 24‐27 ] For quantitative study, inspired by a fundamental work due to the International Confederation for Thermal Analysis and Calorimetry (ICTAC), a protocol was developed to assess the cure kinetics of thermoset composites through isoconversional methods. [ 28,29 ] The kinetic parameters including the apparent activation energy as a function of conversion, the frequency factor of Arrhenius equation, and the exponents of autocatalytic and noncatalytic reactions, contributed from the crosslinking reactions taking place in thermoset composites, were accordingly obtained to understand the role of fillers in network formation in the thermoset resin.…”

Section: Introductionmentioning

confidence: 99%

Cure Kinetics of Silicone/Halloysite Nanotube Composites

Karami

Jazani

Navarchian

et al. 2020

Vinyl Additive Technology

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Properties of silicone thin films and coatings are strongly hooked on curing reaction. We discussed about cure process of silicone nanocomposites containing halloysite nanotube (HNT) at different loading levels (0.5, 1.0, and 2.0 phr), both qualitatively and quantitatively. Systems containing pristine and aminosilane‐functionalized HNT were cured nonisothermally and heat buildup of the reaction was recorded by differential scanning calorimetry (DSC) in terms of the time and the temperature varying the heating rate. Integral and differential isoconversional methods suggested that apparent activation energy (Ea) was strongly affected by the loading level and surface treatment of HNT. The exponent of the autocatalytic reaction (m) was decreased by the introduction and increasing the amount of pristine, and more remarkably the functionalized HNT to the silicone, where the Friedman method suggested 0.249, 0.119, and 0.045 values of m for the neat silicone rubber, and the nanocomposites containing 1 phr of pristine and functionalized HNT, respectively. The logarithm of frequency factor, ln A was also increased due to the enhanced collisions between curing moieties in the presence of pristine and functionalized HNTs form 23.57 seconds for silicone rubber to 24.25 seconds and 25.19 seconds for silicone nanocomposite containing 2 phr of pristine and functionalized HNT, respectively. The theoretical rate of reaction was in agreement with experimental data.

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Development of Mg-Zn-Al-CO3 ternary LDH and its curability in epoxy/amine system

Cited by 37 publications

References 33 publications

Curing Kinetics and Thermal Stability of Epoxy Composites Containing Newly Obtained Nano-Scale Aluminum Hypophosphite (AlPO2)

Curing Kinetics and Thermal Stability of Epoxy Composites Containing Newly Obtained Nano-Scale Aluminum Hypophosphite (AlPO2)

Kinetics of Cross-Linking Reaction of Epoxy Resin with Hydroxyapatite-Functionalized Layered Double Hydroxides

Cure Kinetics of Silicone/Halloysite Nanotube Composites

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