[article]
| Titre : |
Eco-friendly organic coatings based on true self-curable polyepoxides for cathodic electrodeposition |
| Type de document : |
texte imprimé |
| Auteurs : |
Aadamvir Singh, Auteur ; Raju, Auteur ; Pramod Kumar, Auteur |
| Année de publication : |
2012 |
| Article en page(s) : |
p. 55-62 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Catégories : |
Dépôt électrolytique
Epoxydes
Réticulation (polymérisation)
Revêtements
Revêtements organiques
|
| Index. décimale : |
667.9 Revêtements et enduits |
| Résumé : |
True self-curable CED resin system has been developed by using polyepoxide resins based on phenol-novolacs. For this, phenol-novolacs (PNs) of four molar ratios of phenol to formaldehyde viz. 1:0.6, 1:0.7, 1:0.8 and 1:0.9 were synthesized in acidic medium, which were subsequently epoxidized with epichlorohydrin to make epoxy phenol-novolac (EPN) resins of different molecular weights. The prepared resins were characterized by FTIR spectroscopic technique for their structure elucidation and by gel permeation chromatography (GPC) for molecular weight determination. EPNs were reacted with varying molar ratios of a secondary amine; such as diethanolamine (DEtOA), to produce EPN-DEtOA adducts having tertiary amino groups introduced into their molecules. The suitable molar ratio of DEtOA to EPN varied with the molecular weight of EPN, which was higher for EPN of higher molecular weight. These tertiary amino groups would, in fact, initiate the self-curing (polymerization) of resins as applied films, by using free epoxy groups of epoxy-amine adducts, via anionic polymerization. As a consequence, EPN-DEtOA adducts could self-cure without any additional/external crosslinker, even in the co-reacted form. The adducts (modified EPNs) were rendered water-soluble by neutralizing with acetic acid. Aqueous solutions of acetic acid-neutralized adducts were used as electrolytic compositions for the deposition of films of modified polyepoxide (adduct) coatings on metallic panel (workpiece) used as cathode of the electrodeposition cell. By carrying out judiciously planned experiments for cathodic electrodeposition, the electrodeposition characteristics, such as electrodepo- sition yield, dry film thickness and coulombic yield, were determined and optimized. The cathodically electrodeposited films, after self-curing, were characterized for their physical properties, chemical resistance and corrosion protection performance. |
| Note de contenu : |
- EXPERIMENTAL : Materials - Methods - Synthesis of CED coating binders - Cathodic electrodeposition of films
- RESULTS AND DISCUSSION : FTIR spectroscopy - Gel permeation chromatography (GPC) - Characteristics of polyepoxide (EPN) resin - Cathodic electrodeposition of adduct films - Self-curability of adduct as cathodically electrodeposited films - Physical properties of CED films - Chemical resistance properties of CED films - Corrosion protection performance of CED films |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15651 |
in PAINTINDIA > Vol. LXII, N° 6 (06/2012) . - p. 55-62
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