Fluorescence and IR characterization of epoxy cured with aliphatic amines

Rigail-Cedeño, Andrés; Sung, Chong Sook Paik

doi:10.1016/j.polymer.2005.04.063

Cited by 57 publications

(37 citation statements)

References 25 publications

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“…Therefore, the technique could not be used to obtain the curing degree in the first stage of the curing process. Rigail‐Cedeno and Suñg15 studied the curing process of the DGEBA‐amine system and verified the same behavior.…”

Section: Resultsmentioning

confidence: 63%

“…The band at 4534 cm −1 was attributed to a combination of the stretching fundamental (3050 cm −1 ) with the CH 2 deformation fundamental (1460 cm −1 ) of the epoxy ring 14, 15, 33. The FT‐NIR spectra of the heat‐treated prepreg with time are shown in Figure 3.…”

Section: Resultsmentioning

confidence: 99%

“…The epoxy conversion (α NIR ) was calculated with eq. (1) with the NIR absorption peaks: where A E 0 , and A R 0 , are the initial areas of the bands at 4530 and 4623 cm −1 , attributed to the epoxy and phenyl groups (internal reference), respectively, and A E,t and A R,t are their corresponding values at a given time t 13–16…”

Section: Methodsmentioning

confidence: 99%

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Thermal curing of glass‐epoxy prepregs by luminescence spectroscopy

Sales

Diniz

Dutra

et al. 2010

J of Applied Polymer Sci

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In this study, we investigated the application of the luminescence spectroscopy technique in steady-state conditions to study glass fiber-epoxy F161 prepregs. We conducted this study by comparing the results obtained from the intrinsic fluorescence with Fourier transform near infrared spectroscopy. The extrinsic fluorescence of 9-anthroic acid (9-AA) was also used. Fourier transform infrared spectroscopy was also used to characterize the epoxide resin. The prepregs containing 9-AA and those that did not were heat-treated at 177 C (F161) for 1100 min at a 2 C/min heating rate. The results obtained by both methods indicated that the crosslinking reaction could be monitored by analysis of the spectral changes of the emission bands of the prepreg and 9-AA. The intrinsic emission at 320 nm was attributed to the fluorophore group containing the epoxy ring and was used to calculate the conversion degree. The photophysical behavior of the 9-AA probe indicated a reduction of free volume of the polymeric matrix with curing process.

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Section: Resultsmentioning

confidence: 63%

Section: Resultsmentioning

confidence: 99%

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Thermal curing of glass‐epoxy prepregs by luminescence spectroscopy

Sales

Diniz

Dutra

et al. 2010

J of Applied Polymer Sci

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“…No emission was detected from the sample baked at 180°C, which is expected due to the increase of quenching groups as the cure proceeds. 8 The other samples had a clear maximum that, as Tb increased, moved to higher excitation and emission wavelengths. As Tb increased, the energy gap (Table 1) of the absorption between the fundamental state and the excited absorbing state decreased from 3.26 to 2.26 eV, while the gap between the fundamental state and the excited emission state decreased from 2.82 to 2.07 eV.…”

Section: Resultsmentioning

confidence: 93%

“…On the basis of these, several methods were proposed to evaluate the cure degree and the oxidation process of the epoxy resin. [7][8][9] Epoxy resins can be produced with a wide variety of prepolymers and hardeners as well as catalyzers, yielding resins with different surface distributions of chemical groups. This should yield specific interfacial tension (ΓSL) and, consequently, different wetting efficiencies.…”

Section: Introductionmentioning

confidence: 99%

Wettability under Imposed Flow as a Function of the Baking Temperatures of a DGEBA Epoxy Resin Used in the Crude Oil Industry

et al. 2007

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The baking temperature (Tb) of an epoxy resin was optimized in order to decrease the dynamic interfacial tension, identifying the lowest wettability conditions for liquids flowing at a high rate. The dependence of dynamic interfacial tension on Tb was evaluated for the diglycidyl ether of bisphenol A. This resin was used to coat a sucking rod at the oil field of Bacia de Sergipe/Alagoas, Brazil in order to reduce blockage occurrences, maintenance stops, and the pumping capacity required. The samples were baked for 24 h between 100 and 180°C. Their color and absorption spectra showed progressive dependence of Tb, indicating a migration from polymerization, through polymer network degradation, until carbonization. Spectrofluorimetry showed an initial increase in the energy gap between absorption and emission followed by a decrease that was attributed to changes of the chemical environment isotropy. Fourier transform infrared spectroscopy showed that the maximum polymerization occurred at 140°C. Dynamic interfacial tension was evaluated by fluorescence depolarization of induced flowing liquids, using polarized laser-induced fluorescence within induced liquid flows and was clearly dependent on Tb. The lowest dynamic wettability was at 120°C, just before full polymerization, which was attributed to two competing effects as Tb increased: polymerization and progressive yielding of compounds from the epoxy degradation. This points to the need to review the standard application procedures of these resins.

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Preparation and characterization of epoxidate poly(1,2‐butadiene)–toughened diglycidyl ether bisphenol‐A epoxy composites

Wang

2009

J of Applied Polymer Sci

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By the oxidation of liquid poly(1,2-butadiene) (LPB) with H 2 O 2 /HCOOH, epoxidate poly(1,2-butadiene) (ELPB) was obtained as a toughening agent to prepare diglycidyl ether bisphenol-A (DGEBA) epoxy composites by using V115 polyamide(PA) as a cross-linking agent. DGEBA, ELPB, and the composites were effectively cured by PA at 100 C for 2 h followed by postcuring at 170 C for 1 h. Thermal gravimetric analysis results in air and nitrogen atmosphere showed that the thermal stability of composites could be improved by the addition of ELPB. Compared with DGEBA/PA, the composites exhibited a decrease in strength at yield but an increase in strain at break with the increase in ELPB amount. The composite with 10% ELPB exhibited both thermal stability and tenacity superior to those of DGEBA/PA and composites with 5 and 20% ELPB, respectively. The improvements in thermal and mechanical properties of composites depended on the formation of Inter Penetrating Networks (IPN) among DGEBA/ PA/ELPB and their distributions in the matrix. At an appropriate ELPB amount, the IPN, mostly made of DGEBA/PA/ELPB, may be distributed more evenly in the matrix; less ELPB resulted in the formation of IPN mainly made of DGEBA/PA; excessive addition of ELPB resulted in the local aggregation of ELPB/PA and phase separations. The toughening mechanism was changed from chemically forming IPN made of DGEBA/PA/ELPB to physically reinforcing DGEBA/PA by ELPB/PA with the increase in ELPB addition.

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Fluorescence and IR characterization of epoxy cured with aliphatic amines

Cited by 57 publications

References 25 publications

Thermal curing of glass‐epoxy prepregs by luminescence spectroscopy

Thermal curing of glass‐epoxy prepregs by luminescence spectroscopy

Wettability under Imposed Flow as a Function of the Baking Temperatures of a DGEBA Epoxy Resin Used in the Crude Oil Industry

Preparation and characterization of epoxidate poly(1,2‐butadiene)–toughened diglycidyl ether bisphenol‐A epoxy composites

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