Epoxy/Ionic Liquid-Modified Mica Nanocomposites: Network Formation–Network Degradation Correlation

Abstract

We synthesized pristine mica (Mica) and N-octadecyl-N’-octadecyl imidazolium iodide (IM) modified mica (Mica-IM), characterized it, and applied it at 0.1–5.0 wt.% loading to prepare epoxy nanocomposites. Dynamic differential scanning calorimetry (DSC) was carried out for the analysis of the cure potential and kinetics of epoxy/Mica and epoxy/Mica-IM curing reaction with amine curing agents at low loading of 0.1 wt.% to avoid particle aggregation. The dimensionless Cure Index (CI) was used for qualitative analysis of epoxy crosslinking in the presence of Mica and Mica-IM, while qualitative cure behavior and kinetics were studied by using isoconversional methods. The results indicated that both Mica and Mica-IM improved the curability of epoxy system from a Poor to Good state when varying the heating rate in the interval of 5–15 °C min−1. The isoconversional methods suggested a lower activation energy for epoxy nanocomposites with respect to the blank epoxy; thus, Mica and Mica-IM improved crosslinking of epoxy. The higher order of autocatalytic reaction for epoxy/Mica-IM was indicative of the role of liquid crystals in the epoxide ring opening. The glass transition temperature for nanocomposites containing Mica and Mica-IM was also lower than the neat epoxy. This means that nanoparticles participated the reaction because of being reactive, which decelerated segmental motion of the epoxy chains. The kinetics of the thermal decomposition were evaluated for the neat and mica incorporated epoxy nanocomposites epoxy with varying Mica and Mica-IM amounts in the system (0.5, 2.0 and 5.0 wt.%) and heating rates. The epoxy/Mica-IM at 2.0 wt.% of nanoparticle showed the highest thermal stability, featured by the maximum value of activation energy devoted to the assigned system. The kinetics of the network formation and network degradation were correlated to demonstrate how molecular-level transformations can be viewed semi-experimentally.

Chemical and Mechanical Characterization of Unprecedented Transparent Epoxy–Nanomica Composites—New Model Insights for Mechanical Properties

“…The data reported in Table 2 and Figure S5 show that the parameters were not significantly affected by the introduction of mica fillers, in agreement with the data reported in the literature [ 60 , 61 ], where mica was less active compared with silica and CaCO 3 toward thermal decomposition. As for residue values at 700 °C ( Figure S6 ), a linear positive trend was found within the composition range for both Mica 10 and Mica 45 nanocomposites, in agreement with the consideration that by increasing the amount of inorganic filler, the final residue made of char and filler must increase.…”

Preparation and thermal cross-linking mechanism of co-polyester fiber with flame retardancy and anti-dripping by in situ polymerization

“…However, there is no mention of the effect of the synergistic cross-linking effect of flame retardants and inorganic compounds on flame retardant properties. Jouyandeh et al 40 synthesized pristine mica (Mica) and N -octadecyl- N ′-octadecyl imidazolium iodide (IM) modified mica (Mica-IM) and characterized it used. The results indicated that the kinetics of the network formation and network degradation were correlated to demonstrate how molecular-level transformations can be viewed semi-experimentally, but the synergistic cross-linking of additives is not mentioned.…”

Designing a novel polythioether/multiwall carbon nanotube nanocomposites: A complete overview of mechanical, thermal, and morphological properties

“…By adding CNTs to the formulation, a significant increase can be observed in the decomposition temperature as the decomposition initiation temperature raised from 260 to 340 C. Addition of CNTs in polymer matrix led to increases in all of the T IDT , T max , and ash content (Table 9). The state of nanotube dispersion within the polymer matrix may give useful insights into the thermal degradation behavior, [48][49][50][51] which reveal good distribution of CNTs through the polymer matrix. As per Table 9, there was a rise in ash content by adding CNTs in the system because of the very high thermal stability of the CNTs.…”