Effects of graphene oxides on the cure behaviors of a tetrafunctional epoxy resin

Abstract

The influence of graphene oxides (GOs) on the cure behavior and thermal stability of a tetrafunctional tetraglycidyl-4,4’-diaminodiphenylmethane cured with 4,4’-diaminodiphenylsulfone was investigated by using dynamic differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The dynamic DSC results showed that the initial reaction temperature and exothermal peak temperature decreased with the increase of GO contents. Furthermore, the addition of GO increased the enthalpy of epoxy cure reaction. Results from activation energy method showed that activation energies of GO/epoxy nanocomposites greatly decreased with the GO content in the latter stage, indicating that GOs significantly hindered the occurrence of vitrification. The oxygen functionalities, such as hydroxyl and carboxyl groups, on the surface of GOs acted as catalysts and facilitated the curing reaction and the catalytic effect increased with the GO contents. TGA results revealed that the addition of GOs decreased the thermal stability of epoxy

A facile way to produce epoxy nanocomposites having excellent thermal conductivity with low contents of reduced graphene oxide

“…The maximum degradation temperature, T max , and the temperature of 50% mass loss, T 50% , both remained largely unchanged, see Table 3. The changes observed in T on and W 350 are indicative of decreasing thermal stability with increasing rGO content, although increases in thermal stability with increasing rGO content have also been reported in the literature [11,38].…”

Enhanced thermal and mechanical properties of epoxy composites by mixing thermotropic liquid crystalline epoxy grafted graphene oxide

“…The existence of O element is due to the oxygen-containing functional groups, which is in good agreement with FT-IR analysis. So pristine GO is not thermally stable, and mass loss starts even below 100°C and is rapidly at 150°C [13,31], which are respectively attributed to evaporation of the remaining water and the decomposition of labile oxygen groups [32]. In contrast, the weight loss of TLCP-g-GO starts at 280°C, which is roughly 130°C higher than that of GO.…”

Targeted kinetic strategy for improving the thermal conductivity of epoxy composite containing percolating multi-layer graphene oxide chains

“…have been taken into account; however, the property improvements are still far from expectations and the thermal conductivity in particular [3][4][5]. The polymerization of monomers into the polymer matrix is of vital importance to the final properties of composites, several kinetic works reported the effect of GMs on the polymerization [6][7][8][9][10][11], specifically, Wu et al [6] found a vulcanization stage dependence of activation energy (E) variation of graphene/natural rubber system with Ozawa and Kissinger methods; Wang and Qiu [7] noticed an accelerated isothermal melt crystallization of poly (l-lactic acid) by graphene oxide (GO) with isoconversional method; Jing and Qiu [8] (3-hydroxybutyrate) depends on the GO loading and the crystallization temperature; Zhang et al [9] used Kissinger equation and noticed that GO decreases the E of nylon 6; Qiu et al [10] used isoconversional method and found that the effect of GO on the E of a tetrafunctional tetraglycidyl-4,4"-diaminodiphenylmethane cured with 4,4"-diaminodiphenylsulfone depends on GO content and curing stage; and with Kamal and Ryan's model as well as Isayev and Deng's model, Allahbakhsh et al [11] revealed that E of GO/ethylene-propylene-diene rubber system depends on the GO content and the dispersion quality of GO. Notably, hardly any kinetic works directly contribute to the performance improvement of GM/polymer composites, worse still, the polymerizing strategy for the polymer matrices are extensively misused for the GM/polymer composites.…”