Mechanism of the significant improvement in corrosion protection by lowering water sorption of the coating

Zhang, S.-Y; Li, S.-J; Luo, Xiao-Wen; Zhou, Wei‐Fang

doi:10.1016/s0010-938x(00)00042-1

Cited by 32 publications

(10 citation statements)

References 8 publications

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“…Although mechanical properties of epoxy resins are generally considered to be decreased essentially by a plastisizing effect, the hydrolysis reactions (scission of polymer chains) and water with double hydrogen bonds acting as a physical cross-link can also operate. Nowadays, at least two types of water molecules in the epoxy networks depicted as free/bound water have been generally conceived. − To obtain a clear picture of the diffusion process, various techniques have been employed in this field, such as near-infrared Fourier transform infrared spectroscopy (NIR−FTIR), , attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), − ultraviolet (UV) reflection, solid-state nuclear magnetic resonunce (NMR), , dielectric relaxation measurements, ,− positron annihilation lifetime spectroscopy (PALS), − electrochemical impendence spectroscopy (EIS), , fluorescence, and molecular simulations …”

Section: Introductionmentioning

confidence: 99%

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Water Transportation in Epoxy Resin

Zhang

Chen

et al. 2005

Chem. Mater.

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In the present work, water sorption behaviors at different temperatures ranging from 20 to 80 °C were monitored in a model Novolac cured epoxy resin (EP) and its esterfied ramifications (with CH 3 COO, CH 3 CH 2 CH 2 COO, and C 6 H 5 CH 2 COO side groups referred to as EPA, EPB, and EPP, respectively). In light of gravimetric measurements and positron annihilation lifetime spectroscopy, a sorption mechanism was established, which suggested that the equilibrium water content was thermodynamically controlled, while the diffusion process was kinetically controlled. The driving force of the diffusion resulted in energy released by the hydrogen bonds, whereas the transportation rate was essentially subject to the local-chain mobility as well as the dissociation of water molecules from the epoxy network. To verify this model, dynamic mechanical analysis and time-resolved attenuated total reflection Fourier transform infrared spectroscopy experiments were employed. With generalized two-dimensional correlation analysis, the results obtained from IR spectra were consistent with the mechanism proposed.

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Section: Introductionmentioning

confidence: 99%

“…Remarkable progress has been achieved owing to a lot of excellent work published. − However, the information is still far from being well established.…”

Section: Introductionmentioning

confidence: 99%

Water Transportation in Epoxy Resin

Zhang

Chen

et al. 2005

Chem. Mater.

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“…The protective action of the coating is related to the barrier properties with respect to oxygen, water and ion transport from the medium to the metallic substrate. Therefore, water absorption is one of the important factors in determining the protection efficiency of the coating (Pérez et al , 1999, 1999; Zhang et al , 2000; Zhang et al , 2002). The water absorption phenomenon in coatings is assumed to be mainly caused by the diffusion process under concentration gradients.…”

Section: Discussionmentioning

confidence: 99%

Effect of polyaniline/montmorillonite content on the corrosion protection of epoxy coating

Zhang

Shao

Shi

et al. 2017

ACMM

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Purpose The purpose of this paper was to research the influence of polyaniline/montmorillonite (PANI/OMMT) composite powder content on the corrosion protection of epoxy (EP) coating. Design/methodology/approach The polyaniline/montmorillonite/epoxy (PANI/OMMT/EP) coatings containing different contents of PANI/OMMT composite powder were prepared on steel. The corrosion protection performances of PANI/OMMT/EP coatings in 3.5 per cent NaCl solutions were investigated by electrochemical impedance spectroscopy. The barrier property of coatings was examined using water absorption analysis. The structure and crosslink density of coatings were examined using scanning electron microscopy and differential scanning calorimetry, respectively. Findings The PANI/OMMT composite powder could enhance the barrier properties of the EP coating and reduce the corrosion rate of the steel beneath the coating. The coating showed the best corrosion protection performance when 3 per cent PANI/OMMT powder was added to the coating. Originality/value The research clarified the influence of PANI/OMMT content on the corrosion protection of coating from two aspects: one is the barrier performance of the coating; the other is the corrosion inhibitors for metal substrate.

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“…[3][4][5][6][7][8] The elimination of extensive water uptake into these polymers is thus a long-standing goal of materials scientists, however, generally, epoxy resins are well-established to be hygroscopic materials, capable of adsorbing 2%-5% water upon immersion. [9][10][11][12] One potential underlying source of hygroscopicity in highly cross-linked epoxy resin materials is their recently confirmed internal nanostructure. [13][14][15] This is comprised of heterogeneously cross-linked nodular domains, which are expected to provide low energy pathways, giving a structural basis for the relatively low fracture toughness of epoxy network materials, and their high permeability.…”

Section: Introductionmentioning

confidence: 99%

“…Nonetheless, extensive environmental water sorption into these network polymers is known to accelerate oxidative degradation and induce swelling, cracking, and plasticisation 3–8 . The elimination of extensive water uptake into these polymers is thus a long‐standing goal of materials scientists, however, generally, epoxy resins are well‐established to be hygroscopic materials, capable of adsorbing 2%–5% water upon immersion 9–12 …”

Section: Introductionmentioning

confidence: 99%

Internal topology and water transport in tetrafunctional epoxy resins

Morsch

Lyon

Gibbon

et al. 2022

J of Applied Polymer Sci

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Water sorption into epoxy resins limits the performance lifetime of many composites, adhesives, and coatings. One hypothesis for the well‐known hygroscopicity of epoxies is that the well‐known internal nodular topology of epoxy networks enhances permeability. This theory has however remained untested to date, since previous attempts to manipulate the internal topology have been accompanied by changes in the hydrogen bonding capability of resins, which dominates water uptake. Here, the nanostructure of highly cross‐linked network polymers based on tetra glycidyl diaminodiphenyl methane is varied in the absence of significant polarity effects by careful optimization of the cure schedule. The internal morphology of resins cured at 100, 150, and 200°C are characterized using Peakforce tapping mode atomic force microscopy, whilst the cure progression at each temperature is analyzed using in‐situ transmission mode infrared spectroscopy. Distinct nodular morphologies are found to form at high cure temperatures (150 and 200°C), where spectroscopic analysis demonstrates that excess epoxy consumption occurs prior to the gel point, as a result of intra‐cluster cross‐linking and reduced reaction selectivity. Surprisingly, the establishment of an internal nanostructure is, however, found to have negligible effect on the extent and kinetics of moisture sorption.

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Mechanism of the significant improvement in corrosion protection by lowering water sorption of the coating

Cited by 32 publications

References 8 publications

Water Transportation in Epoxy Resin

Water Transportation in Epoxy Resin

Effect of polyaniline/montmorillonite content on the corrosion protection of epoxy coating

Internal topology and water transport in tetrafunctional epoxy resins

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