Determination of the optimum epoxy/curing agent ratio: A study of different kinetic parameters

Núñez, Lisardo; Fraga, F.; Fraga, L.; Salgado, Tânia Denise Miskinis; Anon, Jagadisha

doi:10.1351/pac199567071091

Cited by 16 publications

(7 citation statements)

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“…Fraga et al (2008) reported that the bands at 1507 and 820 cm -1 could be assigned to the p-phenylene groups in the unreacted epoxide group. The disappearance of bands, as observed in the neat epoxy (ENC0), indicated that all of the epoxide groups reacted during curing and were well blended with the isophorone diamine curing agent (Nunez et al 1995;Fraga et al 2008). In the ENC nanocomposites, the epoxide group could react with the hydroxyl groups on the NC surfaces.…”

Section: Fourier Transform Infrared Spectroscopy Of Nanocellulose (Ncmentioning

confidence: 93%

Anticorrosion Properties of Epoxy/Nanocellulose Nanocomposite Coating

et al. 2017

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Nanocellulose (NC) is an attractive reinforcement agent that can be incorporated into protective coatings because it is a renewable, biodegradable, and biocompatible polymer resource. In this study, a series of epoxy resin-based nanocomposites were prepared in the form of coatings with various amounts of NC loadings, and the coatings were applied onto mild steel at room temperature. The characterizations of the NC and nanocomposites were performed via X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and Fourier transform infrared spectroscopy (FTIR). The thermophysical properties of the nanocomposites were evaluated using differential scanning calorimetry (DSC) and thermogravimetry (TGA) analyses. The transparency of the nanocomposite specimens was examined by ultraviolet visible (UV-Vis) spectroscopy in the range of 300 to 800 nm. The corrosion protection properties of the coated mild steel substrates immersed in a 3.5% NaCl solution were studied comparatively by electrochemical impedance spectroscopy (EIS). The results showed that all of the nanocomposite coatings with NC noticeably influenced the epoxy-diamine liquid pre-polymer, both physically and chemically. Furthermore, the 1 wt.% NC nanocomposite coating system was found to have the most pronounced anti-corrosion properties, as confirmed by a 30-day EIS study.

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Section: Fourier Transform Infrared Spectroscopy Of Nanocellulose (Ncmentioning

confidence: 93%

Anticorrosion Properties of Epoxy/Nanocellulose Nanocomposite Coating

et al. 2017

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“…An overall activation energy E a for the polymerization can also be obtained from t g of the curing process at isothermal T i ;25–27 as shown in eq 7, t i can be replaced with t g . The linear relationship of ln t g versus 1/ T i (Fig.…”

Section: Resultsmentioning

confidence: 99%

Application of a model‐free isoconversional method to the cure of phenolic systems

Järvelä

2001

J Polym Sci B Polym Phys

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The curing process of a phenolic resole was monitored with differential scanning calorimetry under nonisothermal and isothermal conditions, the curing kinetics were analyzed with a model-fitting approach and a model-free isoconversional method, and the activation energy of this phenolic system was found to be close to 46 Ϯ 4 kJ mol Ϫ1 . For complicated cures, the model-free isoconversional method was found to be a simpler and more reliable approach.

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“…Errors originating from manual or automatic mixing are largely random in type and intensity and can impact the process significantly. Nunez et al [35] found that deviation in the curing agent ratio by just 1 part per hundred (phr) (from 34 to 35 phr) that was added to a DEGBA epoxy resin, lead to a decrease in the enthalpy of the reaction by $23 J/g and the glass transition temperature by 4 C. Decreases of these key properties in that range are operationally significant as they cause the decrease of curing rate due to reduced exothermic heat flux [36]. The study of Pandiyan Kuppusamy and Neogi [37] shows that the combined deviation of the catalyst and accelerator that were added into an ambient-curing polyester resin from 1 to 2 phr, results in an increase of the peak exotherm temperature by 8 C and an increase of the rate of temperature rise by 5.47 C/ min.…”

Section: Defects Induced By Mixingmentioning

confidence: 99%

Liquid composite molding reproducibility in real-world production of fiber reinforced polymeric composites: a review of challenges and solutions

Konstantopoulos

Hueber

Antoniadis

et al. 2019

Advanced Manufacturing: Polymer & Composites Science

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Liquid composite molding (LCM) suffers from multiple factors that contribute to pronounced uncertainty of process characteristics. This results in compromised reproducibility which is associated to high scrap or the unpredictable behavior of approved parts. However, LCM is still attractive for Fiber-reinforced polymeric composites (FRPC) production due to its economic advantage (i.e. in relation to Autoclave), the capability of some of its variants to produce high performance parts and its potential for process optimization. This review analyzes each uncertainty with respect to its origins and its impact in part or process, based on a combination of past literature and original numerical results. The possible methods to counteract uncertainties are critically discussed, with an eye on both the scientific and feasibility (technical/economical) aspects. The overall aim is to provide to future LCM implementations a roadmap of the most critical challenges and solutions regarding the establishment of a reproducible process.

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Determination of the optimum epoxy/curing agent ratio: A study of different kinetic parameters

Abstract: Abstract

Cited by 16 publications

References 0 publications

Anticorrosion Properties of Epoxy/Nanocellulose Nanocomposite Coating

Anticorrosion Properties of Epoxy/Nanocellulose Nanocomposite Coating

Application of a model‐free isoconversional method to the cure of phenolic systems

Liquid composite molding reproducibility in real-world production of fiber reinforced polymeric composites: a review of challenges and solutions

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