A low resolution pulsed NMR and ultrasound study to monitor the cure of an epoxy resin adhesive

Cocker, R.P.; Chadwick, D. L.; Dare, Diane; Challis, R.E.

doi:10.1016/s0143-7496(98)00013-x

Cited by 24 publications

(18 citation statements)

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“…The NMR measurements were made using a 20MHz instrument with a 4.7 kG magnet (Brucker PCI20 Minispec) [4] at one minute intervals during cure of the same adhesive as above. At each measurement the free induction decay (FlO) [5] curve was decomposed into two constituent exponential signals, one with a short time constant (lOllS to 20IlS) which corresponded to bound but relatively mobile hydrogen nuclei associated with liquid components in the mixture, and one with a long time constant (lOOms to l000ms) which corresponded to relatively immobile hydrogen nuclei associated with solid components in the mixture.…”

Section: Nmr Measurementsmentioning

confidence: 99%

Epoxy Cure Observed by Ultrasound, NMR and WAXS

Challis

Freemantle

Fuller

et al. 1999

Review of Progress in Quantitative Nondestructive Evaluation

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Section: Nmr Measurementsmentioning

confidence: 99%

Epoxy Cure Observed by Ultrasound, NMR and WAXS

Challis

Freemantle

Fuller

et al. 1999

Review of Progress in Quantitative Nondestructive Evaluation

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“…Since small variations of any of these parameters can affect the final mechanical properties of the component, a quality assurance technique either during or post-cure is desirable. The cure process itself has been studied using a variety of techniques such as differential scanning calorimetry (DSC) [1], dynamic mechanical analysis (DMA) [2], nuclear magnetic resonance (NMR) [3] and dielectric [4] and ultrasonic [5] spectroscopy. Each technique is sensitive to a particular aspect of the cure process and therefore much progress in understanding the cure reaction can be made by systematic comparison between them.…”

Section: Introductionmentioning

confidence: 99%

Generic Representation of Cure Monitoring Data Using the Time-Temperature-Transformation (TTT) Diagram: Equivalence Between Dielectric and Ultrasonic Properties

Unwin¹,

Challis²

2004

AIP Conference Proceedings

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Ultrasonic and dielectric cure monitoring techniques have been used to characterize the cure of a typical epoxy-amine adhesive over a range of different cure conditions. The time-temperaturetransformation (TTT) diagram has been used as a generic representation of the data to facilitate comparison between the two techniques. This paper discusses the similarities between the evolving dielectric and ultrasonic properties of the thermoset by investigating the dielectric and ultrasonic loss tangents and the relaxation phenomena observed in each case. Both techniques are shown to be sensitive to variations in cure temperature although for a fixed test frequency the dielectric technique seems to be more sensitive to changes in the early stages of cure whereas at the same frequency the ultrasonic technique appears to be more sensitive to the final stages of the process.

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“…Then, the magnitude of the increasing rate of PS becomes large compared to that of the decreasing rate for PL after the gel effect in the curing reaction occurs. 22 This allows PM to begin to show a decreasing tendency. A change from the increasing to the decreasing tendency in PM, therefore, also indicates the occurrence of an autocatalytic gel effect in this reaction.…”

mentioning

confidence: 99%