Synthesis, characterization, and high potential of 3D metal–organic framework (MOF) nanoparticles for curing with epoxy

Abstract

In this study, the potential of microporous 3D metal-organic framework (MOF) for curing epoxy resin has been discussed. First, MIL-101 (Cr), a chromium based MOF, was synthesized under hydrothermal condition and then characterized by using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and thermogravimetric (TGA) measurements. Epoxy nanocomposites containing 0.1, 0.3 and 0.5 wt.% of MOF nanocrystals were subsequently prepared and their curability was studied in terms of the universal dimensionless Cure Index (CI) criterion under nonisothermal differential scanning calorimetry (DSC). Based on calculations made on the basis of the CI, epoxy nanocomposites containing 0.1, 0.3, and 0.5 wt.% of MOF were labeled Good and Excellent thanks to an enhanced chemical interaction between MOF and epoxy matrix, where the heat of cure in the system was surprisingly even higher than that of the neat epoxy. It was demonstrated that introduction of MOF into epoxy significantly improved the heat release during crosslinking process of epoxy, as indicated by a 63% rise in the enthalpy of cure at MOF loading of 0.1 wt.%. Addition of thermally stable MOF nanomaterials to the epoxy resin improved thermal decomposition resistance of epoxy. Up to 0.3 wt.% loading, the system revealed acceptable thermal stability at elevated temperature featured by more residue remained at the end of test, while sample containing 0.5 wt.% MOF resisted against decomposition at early stages of degradation due to higher thermal stability of MOF with respect to epoxy resin.

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

“…The broad peak appeared irrespective of sample type in the thermograms of samples, which can be considered as a double-peaked curve, where the smaller shoulder overlaps To make an inclusive assessment, we need a powerful measure that integrates all the factors affecting the whole cure process into a simple criterion, known as Cure Index (CI). The applicability and versatility of the CI have been repeatedly proved in previous works [29,30]. To calculate such a measure, one should consider the following equations [10]: Placing the data in Table 1 under scrutiny, it has been demonstrated that the introduction of AHP nanoparticles to the epoxy matrix has contributed to cure reactions of epoxy resin, for all the CI values are laid in Good and Excellent cure states.…”

“…To make an inclusive assessment, we need a powerful measure that integrates all the factors affecting the whole cure process into a simple criterion, known as Cure Index (CI). The applicability and versatility of the CI have been repeatedly proved in previous works [29,30]. To calculate such a measure, one should consider the following equations [10]:…”

Isothermal Vulcanization and Non-Isothermal Degradation Kinetics of XNBR/Epoxy/XNBR-g-Halloysite Nanotubes (HNT) Nanocomposites

“…The vulcanization reaction of a rubber compound can be evaluated through using a differential equation on the basis of time and temperatures of the reaction as the following equation [ 16 , 17 , 18 ]: where α is the degree of cure, dα/dt is the curing rate, t is time, K is the kinetic constant at temperature T and f(α) is function related to the adopted model. The degree of cure parameter is defined as the following relation in the oscillating disc rheometer (ODR) analysis [ 19 ]: where M t is the torque value at time t, M 0 and M ∞ are the torque values at time zero and the end of vulcanization reaction, respectively.…”

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

“…The ultimate properties of cross-linkable polymers such as epoxy thermoset resin strongly depend on the formation of a completely cured network [ 17 ]. In terms of thermosetting epoxy resins, their curability in the presence of any additives and nanofillers has been key for research [ 18 , 19 ]. Therefore, the upward trend for epoxy nanocomposite exploitation necessitates research on the structure–properties correlation [ 20 ].…”