Impedance spectroscopy of reactive polymers. 3. Correlations between dielectric, spectroscopic, and rheological properties during cure of a trifunctional epoxy resin

Mijović, Jovan; Andjelić, Saša; Fitz, Benjamin D.; Zurawsky, Walter; Mondragón, Iñaki; Bellucci, Francesco; Nicolais, L.

doi:10.1002/polb.1996.885

Cited by 38 publications

(36 citation statements)

References 14 publications

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“…It can be observed that the evolution of the impedance maximum correlates very well with the evolution of the degree of cure determined by DSC experiments. This correlation which has also been observed in a wide range of other epoxy systems 14,18 can serve as the basis of online cure monitoring using dielectrics.…”

Section: Dielectric Cure Monitoringmentioning

confidence: 62%

“…This behavior is representative of the cases where the spectrum is dominated by the occurrence of charge migration. 18 During the cure, as entities involved in the dielectric response of the material become less mobile and time constants of all processes increase, the imaginary impedance spectrum moves to higher impedance and lower frequencies. Figure 8(b) shows the evolution of the imaginary impedance maximum during the isothermal cure of the epoxy system at 80 C and 90 C alongside the results of calorimetric cure kinetics experiments.…”

Section: Dielectric Cure Monitoringmentioning

confidence: 99%

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Cure kinetics, glass transition temperature development, and dielectric spectroscopy of a low temperature cure epoxy/amine system

Dimopoulos¹,

Skordos²,

Partridge³

2011

J of Applied Polymer Sci

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This article reports a study of the chemical cure kinetics and the development of glass transition temperature of a low temperature (40 C) curing epoxy system (MY 750/HY 5922). Differential scanning calorimetry, temperature modulated differential scanning calorimetry, and dielectric spectroscopy were utilized to characterize the curing reaction and the development of the cross-linking network. A phenomenological model based on a double autocatalytic chemical kinetics expression was developed to simulate the cure kinetics behavior of the system, while the dependence of the glass transition temperature on the degree of cure was found to be described adequately by the Di Benedetto equation. The resulting cure kinetics showed good agreement with the experimental data under both dynamic and isothermal heating conditions with an average error in reaction rate of less than 2 Â 10 À3 min À1 . A comparison of the dielectric response of the resin with cure kinetics showed a close correspondence between the imaginary impedance maximum and the calorimetric progress of reaction. Thus, it is demonstrated that cure kinetics modeling and monitoring procedures developed for aerospace grade epoxies are fully applicable to the study of low temperature curing epoxy resins.

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Section: Dielectric Cure Monitoringmentioning

confidence: 62%

Section: Dielectric Cure Monitoringmentioning

confidence: 99%

Cure kinetics, glass transition temperature development, and dielectric spectroscopy of a low temperature cure epoxy/amine system

Dimopoulos¹,

Skordos²,

Partridge³

2011

J of Applied Polymer Sci

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“…36,37 blends. The PEI was dried for 4 h at 150ЊC and In this aspect, it is interesting, knowing the then dissolved in the epoxy resin at 140ЊC for 20 kinetic of the system under cure, to plot the conmin.…”

Section: Epoxy Systems Toughened Epoxiesmentioning

confidence: 98%

Buildup of thermoset and crystallization of thermoplastics studied by electrical techniques

Friedrich

Vinh‐tung

Boiteux

et al. 1997

J. Appl. Polym. Sci.

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Up to now, few techniques were available that allowed nondestructive in situ characterization of polymerization during the curing of a thermoset resin. Dynamic dielectric measurements made over a wide range of frequencies provide a sensitive and convenient control to follow up the epoxy-amine cure or to follow the formation of the thermoplastic materials. The direct current measurements and the time of flight measurements were developed to confirm interpretation of the electrical techniques in terms of correlations of the evolution of the conductivity and the network formation and also to evaluate the real value of the ion mobility and its evolution in a course of reaction.

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“…2). The purpose of dielectric sensing was to measure the change in the imaginary impedance maximum, which can be correlated to the chemical conversion state of the material [29][30][31]. The data obtained were used for a correlation with chemical conversion using the cure kinetics model presented in [27].…”

Section: Dielectric Sensingmentioning

confidence: 99%

In-situ Curing Strain Monitoring of a Flat Plate Residual Stress Specimen Using a Chopped Stand Mat Glass/Epoxy Composite as Test Material

et al. 2015

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The curing stresses in a newly proposed bi-axial residual stress testing configuration are studied using a chopped strand mat glass/epoxy specimen. In-situ monitoring of the curing is conducted using dielectric and fibre Bragg grating sensors. It is confirmed that a bi-axial residual stress state can be introduced in the specimens during curing and a quantification of its magnitude is presented. An alternative decomposition method used for converting the dielectric signal into a material state variable is proposed and good agreement with models found in the literature is obtained. From the cure cycles chosen it is suggested that any stress build up in the un-vitrified state is relaxed immediately and only stress build up in the vitrified state contributes to the residual stress state in the specimen.

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Impedance spectroscopy of reactive polymers. 3. Correlations between dielectric, spectroscopic, and rheological properties during cure of a trifunctional epoxy resin

Cited by 38 publications

References 14 publications

Cure kinetics, glass transition temperature development, and dielectric spectroscopy of a low temperature cure epoxy/amine system

Cure kinetics, glass transition temperature development, and dielectric spectroscopy of a low temperature cure epoxy/amine system

Buildup of thermoset and crystallization of thermoplastics studied by electrical techniques

In-situ Curing Strain Monitoring of a Flat Plate Residual Stress Specimen Using a Chopped Stand Mat Glass/Epoxy Composite as Test Material

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