Polymers and Polymer Precursor Characterization

Hagnauer, Gary L.

doi:10.1007/978-1-4613-2119-4_9

Cited by 2 publications

(3 citation statements)

References 17 publications

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“…Despite the different cure temperatures, the light transmittance of the sample always started to decrease at about 40% epoxy conversion with curing under condition 1. In a high‐performance liquid chromatography study of a similar epoxy system, the gel times for the samples cured under isothermal conditions at different temperatures always appeared at 40% epoxy conversion,15 and this agreed with our observations. It also implies that the epoxy conversion degree at which the light transmittance started to decrease is related to the gel point of the epoxy prepreg in this study.…”

Section: Resultssupporting

confidence: 90%

“…The study of Hagnauer15 on the cure of an Epon 828/DICY/monuron system, which was similar to the epoxy prepreg, showed that in the early stages of the reaction, the rate of reaction of the epoxy group ( r ) follows first‐order kinetics: where C E is the epoxy concentration and k is the reaction constant. Equation (3) can be transformed with the application of the normal Arrhenius form: where r 1 / r 2 is the ratio of the rates of epoxy consumption at cure temperatures T 1 and T 2 , respectively.…”

Section: Resultsmentioning

confidence: 99%

“…The cure temperature and the ratio of different functional groups also influence the crosslinking density and the glass‐transition temperature ( T g ) of cured epoxy resins 11, 12. Although many studies have been made of this complicated system,13, 14 a clear understanding of the curing mechanism has still not been achieved, and only a few studies have been reported on commercial products containing glass‐fiber reinforcements 15, 16…”

Section: Introductionmentioning

confidence: 99%

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Study of the isothermal curing of an epoxy prepreg by near‐infrared spectroscopy

Wang

Storm

Houmøller

2003

J of Applied Polymer Sci

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ABSTRACT:The commercial epoxy prepreg SPX 8800, containing diglycidyl ether of bisphenol A, dicyanodiamide, diuron, and reinforcing glass fibers, was isothermally cured at different temperatures from 75 to 110°C and monitored via in situ near-infrared Fourier transform spectroscopy. Two cure conditions were investigated: curing the epoxy prepreg directly (condition 1) and curing the epoxy prepreg between two glass plates (condition 2). Under both curing conditions, the epoxy group could not reach 100% conversion with curing at low temperatures (75-80°C) for 24 h. A comparison of the changes in the epoxy, primary amine, and hydroxyl groups during the curing showed that the samples cured under condition 2 had lower initial epoxy conversion rates than those cured under condition 1 and that more primary amine-epoxy addition occurred under condition 2. In addition, the activation energy under cure condition 2 (104 -97 kJ/mol) was higher than that under condition 1 (93-86 kJ/mol), but a lower glass-transition temperature of the cured samples was observed via differential scanning calorimetry. The moisture in the prepreg was assumed to account for the different reaction kinetics observed and to have led to different reaction mechanisms.

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Section: Resultssupporting

confidence: 90%