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Auteur Hyun Wook Jung |
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Ajouter le résultat dans votre panier Affiner la rechercheApplication of polycarbonate diol containing hindered urea to polyurethane-based clearcoats for tuning of scratch-healing properties / Dong Geun Lee in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 17, N° 4 (07/2020)
Titre : Application of polycarbonate diol containing hindered urea to polyurethane-based clearcoats for tuning of scratch-healing properties Type de document : texte imprimé Auteurs : Dong Geun Lee, Auteur ; Sujin Sung, Auteur ; Dae Geun Oh, Auteur ; Young Il Park, Auteur ; Sang-Ho Lee, Auteur ; Jin Chul Kim, Auteur ; Seung Man Noh, Auteur ; Hyun Wook Jung, Auteur Année de publication : 2020 Article en page(s) : p. 963-976 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Analyse mécanique dynamique
Nanotechnologie
Polycarbonates
Polymères autoréparants
Polyuréthanes
Rayures
Revêtement autoréparant:Peinture autoréparante
Rhéologie
VernisIndex. décimale : 667.9 Revêtements et enduits Résumé : Newly synthesized polycarbonate diols containing hindered urea (PCD-HUs) were employed to modify the scratch-healing properties of conventional two-component clearcoats. To elucidate their contributions to the crosslinking properties of the coatings under conventional thermal curing (150°C), the real-time rheological properties of the clearcoat mixtures were measured using a rotational rheometer in the small-amplitude oscillatory shear mode. A dynamic mechanical analysis was carried out to compare the thermomechanical properties of the cured clearcoat free films. PCD-HU, a key component for the tuning of the scratch-healing, was further identified by analyzing the clearcoat layer cured over a phosphated metal substrate with undercoats such as primer and basecoat as a precoated metal (PCM) sheet. Elastic recovery and scratch profiles of the outermost clearcoat layer in the PCM sheet were acquired through nano-indentation and nano-scratch tests by gradually increasing the quantitative normal force. Finally, the healing patterns of the scratches on various clearcoat layers at a certain normal force were visualized by three-dimensional and one-dimensional cross-cut images using atomic force microscopy under specified temperature and healing time conditions. The surface durability provided by the PCD-HU in the clearcoat layer was confirmed by repeated scratching and healing tests on the same surface positions. Therefore, the coating layer containing HU, which possessed similar surface mechanical properties to those of conventional references, exhibited better scratch-healing performance. Note de contenu : - EXPERIMENTAL METHODS : Preparation of PCD-HUs - Preparation of clearcoat coatings and their property measurements - Elastic recovery and scratch-healing properties of the clearcoat layers
- RESULTS AND DISCUSSION : Real-time rheological properties of the clearcoats during the thermal curing - Thermomechanical properties of the clearcoat free films - Indentation and related elastic recovery properties of the cured clearcoat layers in the PCMs - Scratch properties of the cured clearcoat layers in the PCMs - Scratch-healing pattern analysis by AFM - Durability features through repeated scratching and healing proceduresDOI : https://doi.org/10.1007/s11998-019-00316-0 En ligne : https://link.springer.com/content/pdf/10.1007/s11998-019-00316-0.pdf Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34384
in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 17, N° 4 (07/2020) . - p. 963-976[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 21864 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Characterization of clearcoats containing phosphoric acid-functionalized acrylic polyols for automotive precoated metal sheet coatings Type de document : texte imprimé Auteurs : Jae Young Lee, Auteur ; Myung Seon Yi, Auteur ; Ho Cheol Jeong, Auteur ; Jung Teag Kim, Auteur ; Joon Hyun Nam, Auteur ; Seung Man Noh, Auteur ; Hyun Wook Jung, Auteur Année de publication : 2014 Article en page(s) : p. 697-710 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Automobiles -- Vernis Tags : 'Automotive clearcoat' 'Precoated metal sheet' 'Phosphoric acid-functionalized acrylic polyols' 'Glycidyl methacrylate' acid-GMA modified 'Deep-draw formability' 'Crosslinking networks' Index. décimale : 667.9 Revêtements et enduits Résumé : In this study, the various physical and mechanical properties of clearcoats prepared through a new crosslinking method were investigated. The method was aimed at developing clearcoat systems to improve the deep-draw processing and formability performance in precoated metal (PCM) sheets for automotive applications. From phosphoric acid-functionalized acrylic polyols (PAFAPs) first synthesized in this study and glycidyl methacrylate-modified acrylic copolymer (GMAMAC), phosphoric acid-GMA modified acrylic polyols (PAGMAPs) were newly prepared as new binders in automotive clearcoats. Several clearcoats were formulated with different molecular weights and hydroxyl contents from PAFAPs and GMAMAC. Using clearcoats themselves, the crosslinking reactions for these clearcoats were compared by evaluating the curing behaviors with a rigid-body pendulum test (RPT) and the changes of chemical structures via attenuated total reflectance FTIR spectroscopy. The mechanical properties of the clearcoats were systematically characterized, using dynamic mechanical analysis (DMA) and universal testing machine analysis (UTM). Also, various tests were carried out using PCM sheets by depositing clearcoats above the same PCM-based primers and basecoat layers on galvanized steel. The fracture and deformation patterns related to surface damages on the clearcoat surface were visualized using a nano-scratch test, in association with atomic force microscopy. In particular, deep-draw processing tests, based on forming process simulations, were employed to scrutinize the effect of clearcoats developed in this study on the forming feature in PCM sheets. From the results of RPT, DMA, and UTM tests, the primary crosslinking networks of PAGMAPs from the synthesized PAFAPs and GMAMAC, and also succeeding secondary crosslinking networks between PAGMAPs and blocked isocyanates, were closely correlated with the degree of crosslinking (X c), in accordance with the molecular weight between crosslinks (M c), and glass transition temperature (T g). As a result, the presented clearcoats with a long pendulum period, a low rubbery modulus, and a large tensile strain value, which are the significant factors for developing automotive PCM sheet technology, have truly demonstrated more superior formability during the deep-draw process. It is confirmed that properties of clearcoats with toughness and flexibility could be optimally controlled by PAGMAPs for automotive coatings. Note de contenu : - EXPERIMENTAL : - Materials - Characterization methods
- RESULTS AND DISCUSSION : -Reactivity analysis by FTIR spectroscopy - Curing behavior by RPT - Viscoelastic and mechanical properties - Water-swelling and gel-fraction properties - Tensile properties - Deformations of clearcoat surfaces - Deep-draw processing formabilityDOI : 10.1007/s11998-014-9589-4 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-014-9589-4.pdf Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=22052
in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 11, N° 5 (09/2014) . - p. 697-710[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 16538 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Effect of shim configuration on flow dynamics and operability windows in stripe slot coating process Type de document : texte imprimé Auteurs : Gui Hua Han, Auteur ; Si Hyung Lee, Auteur ; Won-Gi Ahn, Auteur ; Jaewook Nam, Auteur ; Hyun Wook Jung, Auteur Année de publication : 2014 Article en page(s) : p. 19-29 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Enduction par filière
Revêtements
Simulation par ordinateurIndex. décimale : 667.9 Revêtements et enduits Résumé : The slot coating method is a strong candidate for the manufacture of secondary batteries and electrodes for electronics. For the production of such devices, one may need to coat multiple lanes simultaneously which is usually done by implementing specially designed stripe shim inside the die manifold. The effects of shim configurations on the stripe-patterned coated film were analyzed in this study. We employed computational and experimental analyses to estimate flow patterns and corresponding desirable operating condition changes for uniform, converging and diverging slit channels. It was found that the slit channel shape, which is determined by the shim design, can manipulate the die-exit velocity distribution, capable of controlling edge shape of the crossflow film thickness profile. However, other than producing a uniform channel, this might decrease the scope of operability windows due to the aggravation of bead break-up near the edge of the slit channel. Note de contenu : - SIMULATION AND EXPERIMENT : Three-dimensional computation for stripe coating flows - Experimental observations for coating flows and operability windows
- RESULTS AND DISCUSSION : Flow simulation within internal die region - Experiments for operability windows and coating profiles - Computational prediction of coating bead region combined with internal channelsDOI : 10.1007/s11998-013-9485-3 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-013-9485-3.pdf Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=20612
in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 11, N° 1 (01/2014) . - p. 19-29[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 16023 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Effect of sloped die lip geometry on the operability window in slot coating flows using viscocapillary and two-dimensional models Type de document : texte imprimé Auteurs : Si Hyung Lee, Auteur ; See Jo Kim, Auteur ; Jaewook Nam, Auteur ; Hyun Wook Jung, Auteur ; Jae Chun Hyun, Auteur Année de publication : 2014 Article en page(s) : p. 47-55 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Enduction par filière
RevêtementsTags : 'Buse à lèvres' 'Vortex en amont' aval' 'Fenêtre inclinée' 'Modèle de Navier-Stokes' Visco-capillaire' Revêtement Index. décimale : 667.9 Revêtements et enduits Résumé : As an indicator for determining the operability window in slot coating flow, the viscocapillary model considering various configurations of upstream and downstream slot die lips was tested and compared with Navier–Stokes two-dimensional model. Bead pressure and sloped lip angle conditions for uniform coating operation demarcated from leaking and bead break-up defects were quantitatively predicted from the position of upstream meniscus from both models. By comparing the results, it is confirmed that the viscocapillary model for many kinds of sloped die lips could predict the operability window accurately. It is also found that there exists vortex or recirculation regimes inside upstream and downstream coating bead regions, depending on the angles of sloped die lips, even for the stable coating flow. The flow control by die lip structure will be usefully applied to design the strategy for the reliable and optimal coating process, including vortex-free windows. Note de contenu : - GOVERNING EQUATIONS FOR COATING BEAD FLOW : Viscocapillary model considering the sloped die configuration - Calculation of 2-D coating bead flow DOI : 10.1007/s11998-013-9504-4 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-013-9504-4.pdf Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=20615
in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 11, N° 1 (01/2014) . - p. 47-55[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 16023 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Effect of upstream meniscus shape on dynamic wetting and operating limits of Newtonian coating liquids in slot coating bead flows Type de document : texte imprimé Auteurs : Won-Gi Ahn, Auteur ; Si Hyung Lee, Auteur ; Jaewook Nam ; See Jo Kim ; Kwan-Young Lee ; Hyun Wook Jung Année de publication : 2018 Article en page(s) : p. 1067-1076 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Angle de contact
Enduction par filière
Fluides newtoniens
Mouillage (chimie des surfaces)
RevêtementsIndex. décimale : 667.9 Revêtements et enduits Résumé : The coating bead flow and operability window for Newtonian coating liquids are theoretically and experimentally investigated in the slot coating process, with a focus on the shape of the upstream meniscus and contact angles. From the flow visualization in the coating bead region, the contact angles of the upstream meniscus were measured by changing the flow rate and web speed under uniform operating conditions. It was confirmed that the dynamic contact angle is closely related to the capillary number in this process, based on the Hoffman–Voinov–Tanner model. The viscocapillary and two-dimensional Navier–Stokes models using the experimentally observed contact angles accurately predicted the coating bead dynamics and operability windows for two Newtonian liquids. Note de contenu : - EXPERIMENTAL SETUP : Properties of coating liquids
- NUMERICAL SIMULATIONS FOR COATING BEAD FLOWS
- RESULTS AND DISCUSSION : Operability windows by models and experiments - Observation of upstream meniscus shape - Comparison of coating bead flows from experiments and 2-D simulations - Effect of contact angles at upstream meniscus on coating bead dynamics - Effect of contact angles at upstream meniscus on operability windowDOI : 10.1007/s11998-018-0059-2 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-018-0059-2.pdf Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31133
in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 15, N° 5 (09/2018) . - p. 1067-1076[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 20232 - Périodique Bibliothèque principale Documentaires Disponible
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