Cure kinetics of epoxy/graphene oxide (GO) nanocomposites: Effect of starch functionalization of GO nanosheets

Jouyandeh, Maryam; Yarahmadi, Elham; Didehban, Khadijeh; Ghiyasi, Samira; Paran, Seyed Mohammad Reza; Puglia, Debora; Ali, Jagar A.; Jannesari, Ali; Saeb, Mohammad Reza; Ranjbar, Zahra; Ganjali, Mohammad Reza

doi:10.1016/j.porgcoat.2019.105217

Cited by 45 publications

(34 citation statements)

References 26 publications

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“…The unimodal exothermic peaks unconditionally observed in DSC thermograms of all samples at all heating rates are indicative of the single-step kinetics of epoxy ring opening [ 39 , 40 ]. The crosslinking reaction of the studied epoxy nanocomposites passes through different reactions, including the primary and secondary amines of curing agent and the etherification reaction caused by hydroxyl groups formed during the epoxide ring opening reaction as well as OH groups of PEG on the surface of MNPs [ 41 , 42 ]. The typical reactions taking place between PEG-modified and PEG-Co 2+ -doped MNPs and the resin springs from the hydroxyl groups of surface functionality (PEG) with epoxy along with amine groups of curing agent.…”

Section: Resultsmentioning

confidence: 99%

Bulk-Surface Modification of Nanoparticles for Developing Highly-Crosslinked Polymer Nanocomposites

et al. 2020

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Surface modification of nanoparticles with functional molecules has become a routine method to compensate for diffusion-controlled crosslinking of thermoset polymer composites at late stages of crosslinking, while bulk modification has not carefully been discussed. In this work, a highly-crosslinked model polymer nanocomposite based on epoxy and surface-bulk functionalized magnetic nanoparticles (MNPs) was developed. MNPs were synthesized electrochemically, and then polyethylene glycol (PEG) surface-functionalized (PEG-MNPs) and PEG-functionalized cobalt-doped (Co-PEG-MNPs) particles were developed and used in nanocomposite preparation. Various analyses including field-emission scanning electron microscopy, Fourier-transform infrared spectrophotometry (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and vibrating sample magnetometry (VSM) were employed in characterization of surface and bulk of PEG-MNPs and Co-PEG-MNPs. Epoxy nanocomposites including the aforementioned MNPs were prepared and analyzed by nonisothermal differential scanning calorimetry (DSC) to study their curing potential in epoxy/amine system. Analyses based on Cure Index revealed that incorporation of 0.1 wt.% of Co-PEG-MNPs into epoxy led to Excellent cure at all heating rates, which uncovered the assistance of bulk modification of nanoparticles to the crosslinking of model epoxy nanocomposites. Isoconversional methods revealed higher activation energy for the completely crosslinked epoxy/Co-PEG-MNPs nanocomposite compared to the neat epoxy. The kinetic model based on isoconversional methods was verified by the experimental rate of cure reaction.

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Section: Resultsmentioning

confidence: 99%

Bulk-Surface Modification of Nanoparticles for Developing Highly-Crosslinked Polymer Nanocomposites

et al. 2020

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“…As the DSC measurement is a useful technique to determine the reaction kinetics parameters, it is used in the form of isothermal method to display the vulcanization kinetics of XNBR/epoxy/XHNT nanocomposites. Figure 9 represents a typical isothermal DSC scan for various XNBR/epoxy/XHNTs nanocomposites at 170 • C. The rate and degree of vulcanization reaction can be predicted from the exothermic peak position and the area under the DSC curves [48,49]. A comparison among DSC curves of various prepared nanocomposites suggested that the nanocomposites containing a higher loading of nanotubes exhibits a higher cross-linking and more rapid vulcanization process [50,51].…”

Section: Vulcanization Kinetics By Differential Scanning Calorimetry (Dsc)mentioning

confidence: 99%

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

et al. 2021

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The effect of several concentrations of carboxylated nitrile butadiene rubber (XNBR) functionalized halloysite nanotubes (XHNTs) on the vulcanization and degradation kinetics of XNBR/epoxy compounds were evaluated using experimental and theoretical methods. The isothermal vulcanization kinetics were studied at various temperatures by rheometry and differential scanning calorimetry (DSC). The results obtained indicated that the nth order model could not accurately predict the curing performance. However, the autocatalytic approach can be used to estimate the vulcanization reaction mechanism of XNBR/epoxy/XHNTs nanocomposites. The kinetic parameters related to the degradation of XNBR/epoxy/XHNTs nanocomposites were also assessed using thermogravimetric analysis (TGA). TGA measurements suggested that the grafted nanotubes strongly enhanced the thermal stability of the nanocomposite.

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“…Moreover, the reduced pre-exponential factor in the case of epoxy composites apparently evidences the decreased chemical collision of active substances in curing reaction. 19 This alludes to the steric effect of the dispersed DFGO sheets on the mobility of the active substances. Accordingly, the facilitation effect of DFGO on the curing reaction exhibits the up and then slightly down trend along with the DFGO loading in the epoxy composites increases from 0.1% to 1.0%, which results in the first decreased and then relatively increased activation energy.…”

Section: Thermal Analysis Of Epoxy Composites With Dfgomentioning

confidence: 99%

“…17,18 For example, starch-functionalized GO nanosheets with rich hydroxyl contribute to epoxy ring opening, which accelerates the curing reactions having low activation energy and large amount of released reaction heat. 19,20 Moreover, GO sheets functionalized with active groups such as diamine will act as co-curing agents for the epoxy resin to increase the interfacial and mechanical properties of epoxy composites. [21][22][23] For example, GO sheets functionalized by amino terminated silane coupling agent contribute to more reinforcement of epoxy composites than epoxy terminated silane coupling agent modified GO sheets because of the better interfacial stress transfer.…”

Section: Introductionmentioning

confidence: 99%

The correlated effects of polyetheramine-functionalized graphene oxide loading on the curing reaction and the mechanical properties of epoxy composites

Tian

Yang

et al. 2021

High Performance Polymers

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In this study, the effects of polyetheramine (D230) functionalized graphene oxide loading on the curing reaction, thermal and mechanical properties of epoxy composites were studied and the correlation between structure and property of epoxy composite was established. In the functionalization of graphene oxide (GO), the effect of the mass ratio of D230 to GO on chemical properties of the functionalized GO was investigated. Results showed that D230 were successfully covalently grafted onto surface of two-dimensional functionalized GO sheet. The functionalized GO sheets prepared under optimal condition of D230/GO ratio of 1:1 dispersed evenly in epoxy composites, indicating the possibility of the epoxy composite fabrication by the solvent-free technique. The analysis of qualitative Cure Index suggested that epoxy composites were subjected to excellent curing. The quantitative evaluation of curing kinetics demonstrated that the functionalized GO exhibited a chemical facilitation on the curing reaction. However, the functionalized GO simultaneously physically restricted the curing reactivity, especially at high loading. These contributed to the improved interfacial properties and high toughness of the epoxy composites. Compared to neat epoxy, the epoxy composites showed effective tensile strength improvement of ∼10.0% (77.0 MPa), tensile modulus enhancement of ∼7.7% (3.34 GPa), flexural modulus increment of ∼12.1% (3.43 GPa), and flexural strength increment of ∼10.6% (124.3 MPa). This study demonstrated an effective and environment-friendly strategy to design GO reinforced epoxy composites with favorable dispersion and interfacial bonding, and it further clarified the relationship between the crosslinking network/interfacial structure and the mechanical properties of epoxy composites.

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Cure kinetics of epoxy/graphene oxide (GO) nanocomposites: Effect of starch functionalization of GO nanosheets

Cited by 45 publications

References 26 publications

Bulk-Surface Modification of Nanoparticles for Developing Highly-Crosslinked Polymer Nanocomposites

Bulk-Surface Modification of Nanoparticles for Developing Highly-Crosslinked Polymer Nanocomposites

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

The correlated effects of polyetheramine-functionalized graphene oxide loading on the curing reaction and the mechanical properties of epoxy composites

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