Dewetting of Unreacted Epoxy/Amine Mixtures on Silica

Woerdeman, Dara L.; Parnas, Richard S.; Giunta, Rachel K.; Wilkerson, Amy

doi:10.1006/jcis.2002.8254

Cited by 5 publications

(8 citation statements)

References 26 publications

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“…This indicates that the DGEBA molecular ion is not detected during the curing reaction at any of the HR ratios. This finding is in line with observation made by Woerdeman et al25 that the DGEBA ion is not detected when the curing reaction is complete. Figure 3(a) also indicates that the C x H y N + ions and the C 3 H 8 + ion feature in the opposite direction (positive) to all other significant ions of C 14 H 7 O + , CHO + , CH 3 O + , C 3 H 7 + , C 3 H 5 + , and C 24 H 21 O + This indicates a discrete physical phenomenon in which the ions in the positive region correspond to the change in hardener concentration while the other ions are related to the change in the resin concentration in the data set.…”

Section: Resultssupporting

confidence: 93%

“…The peaks for data analysis were selected initially based on reference libraries and previous assignments in the literature for DGEBA, DGEBF, and IPD molecules 20, 21, 24, 25. Further, peaks were assigned using the library and the exact mass calculator tool incorporated in the Ionspec software package (Ion‐TOF GmbH, Germany) to identify contaminant peaks, including the hydrocarbon peaks, and peaks that were likely to correspond to fragments of the resin/hardener not listed in the literature.…”

Section: Methodsmentioning

confidence: 99%

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ToF‐SIMS investigation of epoxy resin curing reaction at different resin to hardener ratios

Awaja

Riessen

Kelly

et al. 2008

J of Applied Polymer Sci

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Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and principal components analysis (PCA) were used to analyze diglycidyl ether of bisphenol A (DGEBA) and diglycidyl ether of bisphenol F (DGEBF) epoxy resin blend cured with isophorone diamine (IPD) hardener at different resin to hardener ratios. The aim was to establish correlations between the hardener concentration and the nature and progress of the crosslinking reaction. Insights into the cured resin structure revealed using ToF-SIMS are discussed. showed variance related to the completion of the curing reaction. Relative intensities of C x H y N z þ ions in the cured resin samples are indicative of the un-reacted and partially reacted hardener molecules, and are found to be proportional to the resin to hardener mixing ratio. The relative ion intensities of the aliphatic hydrocarbon ions are shown to relate to the cured resin crosslinking density.

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Section: Resultssupporting

confidence: 93%

Section: Methodsmentioning

confidence: 99%

ToF‐SIMS investigation of epoxy resin curing reaction at different resin to hardener ratios

Awaja

Riessen

Kelly

et al. 2008

J of Applied Polymer Sci

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“…This technique has previously been used on epoxy-amine surfaces to characterize the chemical components. [28] Results produced from the spectrometer indicate a high degree of bromine (m/z ¼ 79 and 81) on the entire surface, confirming release of the brominated epoxy monomer from the microcapsules leading to formation of a new film on the surface.…”

Section: Full Papermentioning

confidence: 95%

Full Recovery of Fracture Toughness Using a Nontoxic Solvent‐Based Self‐Healing System

Caruso

Blaiszik

White

et al. 2008

Adv Funct Materials

244

186

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Two significant advances are reported for solvent‐based self‐healing of epoxy materials. First, an autonomic system yielding complete recovery of fracture toughness after crack propagation was achieved by embedding microcapsules containing a mixture of epoxy monomer and solvent into an epoxy matrix. Healing with epoxy‐solvent microcapsules is superior to capsules that contain solvent alone, and multiple healing events are reported for this system. Second, efficient healing is reported for new solvents, including aromatic esters, which are significantly less toxic than the previously employed solvent, chlorobenzene. Preliminary aging studies using either chlorobenzene or ethyl phenylacetate as the solvent demonstrate the stability of the epoxy‐solvent system under ambient conditions for at least one month.

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“…The peaks for ToF‐SIMS data analysis were selected initially on the basis of reference libraries and previous assignments in the literature for DGEBA, DGEBF, IPD, Teta, and other amine molecules 21–24. Further peaks were assigned with the library and the exact mass calculator tool in Ionspec software (Ion‐TOF), including contaminant peaks, hydrocarbon peaks, and peaks likely to correspond to fragments of the resin/hardener that were not listed in the literature.…”

Section: Methodsmentioning

confidence: 99%

Investigation of the postcure reaction and surface energy of epoxy resins using time‐of‐flight secondary ion mass spectrometry and contact‐angle measurements

Awaja

Gilbert

Fox

et al. 2009

J of Applied Polymer Sci

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Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used to investigate correlations between the molecular changes and postcuring reaction on the surface of a diglycidyl ether of bisphenol A and diglycidyl ether of bisphenol F based epoxy resin cured with two different amine-based hardeners. The aim of this work was to present a proof of concept that ToF-SIMS has the ability to provide information regarding the reaction steps, path, and mechanism for organic reactions in general and for epoxy resin curing and postcuring reactions in particular. Contact-angle measurements were taken for the cured and postcured epoxy resins to correlate changes in the surface energy with the molecular structure of the surface. Principal components analysis (PCA) of the ToF-SIMS positive spectra explained the variance in the molecular information, which was related to the resin curing and postcuring reactions with different hardeners and to the surface energy values. The first principal component captured information related to the chemical phenomena of the curing reaction path, branching, and network density based on changes in the relative ion density of the aliphatic hydrocarbon and the C 7 H 7 O þ positive ions. The second principal component captured information related to the difference in the surface energy, which was correlated to the difference in the relative intensity of the C x H y N z þ ions of the samples. PCA of the negative spectra provided insight into the extent of consumption of the hardener molecules in the curing and postcuring reactions of both systems based on the relative ion intensity of the nitrogen-containing negative ions and showed molecular correlations with the sample surface energy.

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Dewetting of Unreacted Epoxy/Amine Mixtures on Silica

Cited by 5 publications

References 26 publications

ToF‐SIMS investigation of epoxy resin curing reaction at different resin to hardener ratios

ToF‐SIMS investigation of epoxy resin curing reaction at different resin to hardener ratios

Full Recovery of Fracture Toughness Using a Nontoxic Solvent‐Based Self‐Healing System

Investigation of the postcure reaction and surface energy of epoxy resins using time‐of‐flight secondary ion mass spectrometry and contact‐angle measurements

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