Rheological study of the curing kinetics of epoxy–phenol novolac resin

Auad, Marı́a L.; Nutt, Steven; Stefani, Pablo Marcelo; Aranguren, Mirta I.

doi:10.1002/app.24674

Cited by 39 publications

(18 citation statements)

References 40 publications

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“…The isothermal rheological spectra of PF and PRFR‐2, G ′, G ′′, and η with time at 105 °C are shown in Figure . As exhibited in Figure (a,b), the profiles of G ′ and G ′′ of PFR and PRFR‐2 correlated with shape of the profiles of the thermosetting resins as previously reported . At the beginning of the cross‐linking reactions, the modulus and complex viscosity increased slowly because the resins needed higher temperatures or additional time to cure.…”

Section: Resultssupporting

confidence: 84%

“…As exhibited in Figure 7(a,b), the profiles of G 0 and G 00 of PFR and PRFR-2 correlated with shape of the profiles of the thermosetting resins as previously reported. 26 At the beginning of the cross-linking reactions, the modulus and complex viscosity increased slowly because the resins needed higher temperatures or additional time to cure. As time progressed, G 0 , G 00 , and h of the resins increased rapidly and reached fixed values.…”

Section: Resultsmentioning

confidence: 99%

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Resorcinol in high solid phenol−formaldehyde resins for foams production

Liu

Chen

et al. 2017

J of Applied Polymer Sci

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The acid curing agent content and foaming temperature could be reduced by improving the resol reactivity. In this study, highly active and solid phenol−resorcinol−formaldehyde copolymer resins (PRFRs) with different resorcinol/phenol (R/P) molar ratios and formaldehyde/(phenol + resorcinol) [F/(P + R)] molar ratios were synthesized through the copolymerization of resorcinol, formaldehyde, and phenol. Phenol−resorcinol−formaldehyde foams (PRFFs) were prepared with synthetic PRFRs. The results showed that PRFR‐2 exhibited higher reactivity, faster curing speed, and better thermal stability. In addition, the foam produced with the PRFR‐2 had improved mechanical and flame retardation properties and a compressive strength of 0.18 MPa, a flexural strength of 0.25 MPa, and a limited oxygen index (LOI) greater than 37%. The increased reactivity of the PRFRs correlated with the changing mechanical properties of PRFFs because of the effects of resorcinol and the molar ratio of formaldehyde to phenol and resorcinol. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44881.

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Section: Resultssupporting

confidence: 84%

Section: Resultsmentioning

confidence: 99%

Resorcinol in high solid phenol−formaldehyde resins for foams production

Liu

Chen

et al. 2017

J of Applied Polymer Sci

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“…The decrease considered to be a physical softening process that caused only by the temperature of the noncured resin, often symbolized with T g0 . 38 At 21 to 81 minutes, G′, G″, and tan δ of MPR/GF prepreg showed an approximate plateau and reached a minimum value, which is caused by the release of volatiles and the very slow curing reaction during the precuring process. At 81 to 240 minutes, there was a rapid increasing for G′, where G″ and tan δ increased to a peak, firstly, and then, the 2 values decreased gradually in that a large number of curing reaction occurred during the isothermal at 150°C.…”

Section: The Curing Behavior Mpr/gf Prepregmentioning

confidence: 97%

Time‐temperature‐transformation diagram of modified resol phenolic resin and the thermomechanical performance of resol phenolic resin/glass fabric composite

Lei

Jiang

et al. 2018

Polymers for Advanced Techs

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In this paper, modified resol phenolic resin (MPR) and its glass fabric prepreg (MPR/GF prepreg) were fabricated via a hot melt preimpregnated method. To optimize the curing schedule in curing completion, safe processing window, and storage stability conditions, time‐temperature‐transformation diagram dynamic rheological behavior of MPR was established based on such phenomenological changes as viscosity, gelation, and vitrification. The curing behavior of MPR/GF prepreg was further clarified using online monitored dynamic mechanical analysis. At last, thermogravimetric analysis and dynamic mechanical analysis tests were conducted to evaluate the thermomechanical properties of MPR/GF composite. The excellent thermomechanical performance of MPR/GF composite suggests the important role of time‐temperature‐transformation diagram in optimizing the curing cycle and the overall dynamic mechanical properties of the composite.

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“…The profiles of the resin's curing degree can be calculated from a rheological variable such as the complex modulus (G*), the elastic modulus (G 0 ), or the resulting torque (C) value according to different authors. [40][41][42][43] In this work, we used the logarithm of the material's normalized elastic modulus to obtain the mechanical curing degree [a(t)] of resol resin. The elastic modulus was chosen as a suitable rheological variable, because the high G 0 values found caused low dispersion in the measurements.…”

Section: Profiles Of the Resin's Mechanical Curing Degreementioning

confidence: 99%

Isothermal rheokinetic study of a precured resol resin beyond gelation by torsion

Domínguez

Oliet

Alonso

et al. 2011

J of Applied Polymer Sci

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The rheokinetics of the curing process of a resol resin was studied through isothermal analysis. The resin was subjected to a curing pretreatment until gelation was reached. Rectangular torsion was chosen as the appropriate strain form to carry out the study of the resin's curing kinetics, because the viscoelastic behavior of the material was closer to an ideal solid than to a Newtonian fluid. Seven operating temperatures were selected for analysis (80-110 C). The Arrhenius and Kiuna rheokinetic models were applied to the resin's complex viscosity (g*) evolution during the crosslinking of polymer. The resol resin had curing activation energies of 62.6 and 65.8 kJ/ mol when the Arrhenius model was applied in four-and six-parameter forms, respectively. The Kiuna model was proposed to fit the nonlinear viscosity region found at the highest temperatures. This model was suitable to predict changes in the resin's complex viscosity, obtaining a curing activation energy of 69.5 kJ/mol for the resin. In addition, the evolution of the degree of mechanical curing was obtained from the elastic modulus, rather than from the more common DSC technique.

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Rheological study of the curing kinetics of epoxy–phenol novolac resin

Cited by 39 publications

References 40 publications

Resorcinol in high solid phenol−formaldehyde resins for foams production

Resorcinol in high solid phenol−formaldehyde resins for foams production

Time‐temperature‐transformation diagram of modified resol phenolic resin and the thermomechanical performance of resol phenolic resin/glass fabric composite

Isothermal rheokinetic study of a precured resol resin beyond gelation by torsion

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