Determination of gel time and gel point of epoxy-amine thermosets by in-situ near infrared spectroscopy

Zhu, Zhiqiang; Sun, Xiaorong; Yuan, Hairong; Song, Chunfeng; Cao, Yanan; Li, Xiaoyü

doi:10.1016/j.polymertesting.2018.11.001

Cited by 17 publications

(7 citation statements)

References 36 publications

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“…All calculations were performed on three different initial structures and the results so obtained were averaged over them. for epoxy resins 34,35) . The curing reaction proceeded in the same manner in other epoxy/amine combination systems.…”

Section: Simulationsmentioning

confidence: 99%

Molecular Size Effect on Curing Process for Epoxy and Amine Mixture

Yamamoto

Tanaka

2021

J. Soc. Rheol., Jpn

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The curing process of epoxy and amine mixtures was investigated from the viewpoint of molecular size of reactants via all-atom molecular dynamics simulation. Of four mixtures composed of either smaller or larger epoxy and amine molecules, the system of both smaller epoxy and amine reached the highest conversion at a given time, whereas the conversion for the combination of both larger epoxy and amine was the lowest. These can be explained in terms of their diffusion coeffi cients. In addition, the size effect on the reaction kinetics was more striking for epoxy than amine in the curing process. This was because epoxy reacted only once but amine did twice. When the primary amine reacted with epoxy, the resultant secondary amine was incorporated into the three-dimensional network. Hence, even if the primary amine had a higher mobility, the movement of the part after the reaction slowed down, making the further reaction to be the tertiary amine slow. Finally, it was shown that although the smaller epoxy reacted faster than the larger one in the mixed system of larger/smaller epoxy and amine, there was no difference in the reaction progress depending on the molecular size of amine.

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Section: Simulationsmentioning

confidence: 99%

Molecular Size Effect on Curing Process for Epoxy and Amine Mixture

Yamamoto

Tanaka

2021

J. Soc. Rheol., Jpn

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“…25 In the previous work, a method of near-infrared spectroscopy (NIR) combined with wavelet transform was proposed to separate the NIR spectral signals of epoxy group and the signal of scattering light from the in situ spectra. 28 Data processing and statistical analysis were performed with Matlab (The Mathworks, Inc.). The schematic of WT is shown in Fig.…”

Section: Discussionmentioning

confidence: 99%

Characteristic of Five Subpopulation Leukocytes in Single-Cell Levels Based on Partial Principal Component Analysis Coupled with Raman Spectroscopy

Wang

Luo

et al. 2020

Appl Spectrosc

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“…The degree of conversion corresponding to gelation is the gel point, and the reaction time to reach the gel point is the gel time. 5 Gel point is an irreversible reaction in which the weight-average molecular weight reaches infinity. Gel time can be used to determine the activation energy for the cure reaction of the system.…”

Section: Introductionmentioning

confidence: 99%

“…6 Gel time of the prepreg plays an important role for final CCL quality. 5 Accurate knowledge of the gel time would therefore allow the estimation of the optimal temperature and time for which the sample should be heated. 6 If the gel time is too short, the resin may have reacted prematurely and inter sheet bonding between prepreg and copper surface do not form firmly.…”

Section: Introductionmentioning

confidence: 99%

Determination of gel time of prepreg in copper clad laminate industry by near infrared spectroscopy

Liu¹,

Li²,

Zeng³

et al. 2020

Journal of Near Infrared Spectroscopy

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Gel time of prepreg is an important quality determinant in the manufacturing process of Copper Clad Laminate (CCL). Prepreg consists of a glass fiber reinforcement impregnated to a predetermined level with a resin matrix. In this work, near infrared spectroscopy associated with partial least squares (PLS) regression has been applied to analyse the gel time of prepreg samples in the manufacturing process. A total of 250 prepreg samples were randomly divided into a calibration set and a validation prediction set with a ratio of 4:1. The values of Root Mean Square Error of leave-one-out Cross-Validation (RMSECV) and the coefficient of determination (R2) of the calibration model was 2.95 s and 0.92 respectively, with eight PLS factors used. The results of the paired t-test revealed that there was no significant difference between the NIR method and the reference method. The analytical result showed that, NIR spectroscopy was a rapid, nondestructive, and accurate method for real-time prediction of prepreg quality in the CCL manufacturing process.

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Determination of gel time and gel point of epoxy-amine thermosets by in-situ near infrared spectroscopy

Cited by 17 publications

References 36 publications

Molecular Size Effect on Curing Process for Epoxy and Amine Mixture

Molecular Size Effect on Curing Process for Epoxy and Amine Mixture

Characteristic of Five Subpopulation Leukocytes in Single-Cell Levels Based on Partial Principal Component Analysis Coupled with Raman Spectroscopy

Determination of gel time of prepreg in copper clad laminate industry by near infrared spectroscopy

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