Enhancement in adhesive bonding of aluminum alloy by steam treatment studied by energy loss near edge fine structures in electron energy loss spectroscopy

Horiuchi, Shin; Liu, Yida; Hanada, Takeshi; Akiyama, Haruhisa

doi:10.1016/j.apsusc.2022.153964

Cited by 19 publications

(12 citation statements)

References 23 publications

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“…Although in several cases the aluminum specimen broke during the LSS test, overall, the used functionalized propylene terpolymers show a lower adhesive strength to aluminum than to steel. Most likely, differences in morphology and polarity might play an important role. , Initial surface analyses show that the polarity of the aluminum surface is higher than of the steel surface (Table S5, Table S6). More detailed studies need to be performed to elucidate the cause of this difference.…”

Section: Resultsmentioning

confidence: 99%

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Unprecedented Adhesive Performance of Propylene-Based Hydroxyl-Functionalized Terpolymers

Kruszynski

Nowicka

Bouyahyi

et al. 2023

ACS Appl. Polym. Mater.

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The synthesis of hydroxyl-functionalized propylenebased terpolymers and their performance as hot melt adhesives were investigated. The products comprise uniformly distributed butyl and 4-hydroxyl-butyl branches along the polypropylene backbone. Despite the low hydroxyl-functionality level of ≤ 0.5 mol %, hydroxyl-functionalized terpolymers show formidable adhesion to aluminum and steel, providing an adhesive strength exceeding 16 MPa, whereas the nonfunctionalized congeners hardly adhere to these metals. As evidenced by rheological measurements, the functional groups form dynamic crosslinks based on hydrogen bonding and electrostatic interactions with aluminum oxide hydroxide residues, remaining in the product after polymerization. At the industrial application temperature of 180 °C, nondeashed and deashed samples of polymers having 0.1 or 0.5 mol % incorporated 5-hexen-1-ol gave, upon cooling to room temperature, comparable adhesive strengths. Deashing and increasing the functionality level lead to a significant improvement of the adhesion strength at a lower application temperature (130 °C), allowing application of the hydroxyl-functionalized propylene-based terpolymers as high-strength hot melt adhesives for combinations of polypropylene and metals.

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Section: Resultsmentioning

confidence: 99%

“…Most likely, differences in morphology and polarity might play an important role. 61,62 Initial surface analyses show that the polarity of the aluminum surface is higher than of the steel surface (Table S5, Table S6). More detailed studies need to be performed to elucidate the cause of this difference.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Unprecedented Adhesive Performance of Propylene-Based Hydroxyl-Functionalized Terpolymers

Kruszynski

Nowicka

Bouyahyi

et al. 2023

ACS Appl. Polym. Mater.

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“…A similar spectral change was previously observed for the epoxy adhesive/steam-treated Al interface. 25…”

Section: Atomic Force Microscopy (Afm)mentioning

confidence: 99%

Disentangling Origins of Adhesive Bonding at Interfaces between Epoxy/Amine Adhesive and Aluminum

et al. 2023

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Joining metals by adhesive bonding is essential in widespread fields such as mobility, dentistry, and electronics. Although adhesive technology has grown since the 1920s, the roles of interfacial phenomena in adhesive bonding are still elusive, which hampers the on-demand selection of surface treatment and adhesive types. In the present study, we clarified how chemical interactions and mechanical interlocking governed adhesive bonding by evaluating adhesion properties at the interfaces between epoxy/amine adhesive and two kinds of Al adherends: a flat aluminum hydroxide (Al x O y H z ) and technical Al plate with roughness. Spectroscopic and microscopical data demonstrate that the protonation of the amino groups in an amine hardener converts Al(OH)3 on the Al x O y H z surface to AlO(OH). The interfacial protonation results in an interfacial dipole layer with positive charges on the adhesive side, whose electrostatic interaction increases the interfacial fracture energy. The double cantilever beam tests for the flat Al x O y H z and technical Al substrates clarify that the mechanical interlocking originating from the surface roughness further increases the fracture energy. This study disentangles the roles of the chemical interactions and mechanical interlocking occurring at the epoxy adhesive/Al interface in the adhesion mechanism.

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“…5 Besides, ELNES/ XANES spectra are also useful to understand the mechanism and dynamics during chemical reactions. 6 Also, for carbon materials, Suenaga et al used the carbon K-edge ELNES spectra to discriminate the local electronic and atomic structures for graphene. 7 However, the molecular structure, chemical bonding, and various molecular properties, such as magnetic and mechanical properties, are mainly governed by the ground-state electronic structure of the occupied orbital, which cannot be directly obtained from the core-loss spectra.…”

mentioning

confidence: 99%

“…Thus, characterizing the local atomic and electronic structures becomes essential for investigating and designing the nanomaterials. , Among characterization methods for the nanomaterials, core-loss spectroscopy, namely, energy loss near-edge spectroscopy (ELNES) and X-ray absorption near-edge structure (XANES), has been widely used because it reflects the atomic and electronic structures of materials in high spatial resolution and sensitivity. , For example, the electronic states of catalysis can be probed through ELNES/XANES spectra to investigate the oxidation states of catalysis . Besides, ELNES/XANES spectra are also useful to understand the mechanism and dynamics during chemical reactions . Also, for carbon materials, Suenaga et al used the carbon K-edge ELNES spectra to discriminate the local electronic and atomic structures for graphene …”

mentioning

confidence: 99%

Prediction of the Ground-State Electronic Structure from Core-Loss Spectra of Organic Molecules by Machine Learning

Chen

Shibata

Hagita

et al. 2023

J. Phys. Chem. Lett.

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The core-loss spectrum reflects the partial density of states (PDOS) of the unoccupied states at the excited state and is a powerful analytical technique to investigate local atomic and electronic structures of materials. However, various molecular properties governed by the ground-state electronic structure of the occupied orbital cannot be directly obtained from the core-loss spectra. Here, we constructed a machine learning model to predict the groundstate carbon s-and p-orbital PDOS in both occupied and unoccupied states from the C K-edge spectra. We also attempted an extrapolation prediction of the PDOS of larger molecules using a model trained by smaller molecules and found that the extrapolation prediction performance can be improved by excluding tiny molecules. Besides, we found that using smoothing preprocess and training by specific noise data can improve the PDOS prediction for noisecontained spectra, which pave a way for the application of the prediction model to the experimental data.

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Enhancement in adhesive bonding of aluminum alloy by steam treatment studied by energy loss near edge fine structures in electron energy loss spectroscopy

Cited by 19 publications

References 23 publications

Unprecedented Adhesive Performance of Propylene-Based Hydroxyl-Functionalized Terpolymers

Unprecedented Adhesive Performance of Propylene-Based Hydroxyl-Functionalized Terpolymers

Disentangling Origins of Adhesive Bonding at Interfaces between Epoxy/Amine Adhesive and Aluminum

Prediction of the Ground-State Electronic Structure from Core-Loss Spectra of Organic Molecules by Machine Learning

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