Development of low-temperature self-curable water soluble polyepoxide coatings for cathodic electrodeposition / Pramod Kumar in PAINTINDIA, Vol. LII, N° 6 (06/2002)

[article]  inPAINTINDIA > Vol. LII, N° 6 (06/2002) . - p. 45-66 Titre : Development of low-temperature self-curable water soluble polyepoxide coatings for cathodic electrodeposition Type de document : texte imprimé Auteurs : Pramod Kumar, Auteur ; M. K. Trivedi, Auteur Année de publication : 2002 Article en page(s) : p. 45-66 Note générale : Biliogr. Langues : Anglais (eng) Index. décimale : 667.9 Revêtements et enduits Résumé : Epoxidised phenol-novolac (EPN) type of polyepoxide resin was used for developing water-soluble cathodically electro-depositable coatings which could be self-curable without using any external/additional cross-linking agent. The self-curing of cathodically deposited films could be effected at a low temperature of 80°C in 30 min, as compared to 150-170°C in 30 min practised presently in many commercial cathodic electro-deposition (CED) installations. In this work, effect of varying molar ratio of secondary amines such as diethanol amine (DEtOA) and diethyl amine to epoxidised phenol-novolac (EPN) on the solubility of EPN-secondary amine adducts prepared at 80, 60 and 30°C for varying reaction times was investigated. Self-curing characteristics of EPN-DEtOA (1:2 moles) adduct at 30-160°C were studied. Kinetics of film growth during CED was investigated by using aqueous solutions of acetic acid neutralised EPN-DEtOA (1:2 moles) adduct. Variables for kinetic studies were deposition time (30-600 s), applied voltage (5-250 V) and solution concentration (1-20% (w/w)). By carrying out CED of polyepoxide films, values of electro-deposition (ED) characteristics found were: ED yield as 5.89 mg/cm2, Coulombic yield as 19.78 mg/C and dry film thickness (DFT) as 52.12 μm. Plots of DFT vs. deposition time (t), DFT vs, t1/2 and current density vs. field strength were drawn to calculate the values of Coulombic efficiency of the process and film conductivity. Cathodically electro-deposited films were finally characterised for physical properties, chemical resistance and corrosion protection performance. Note de contenu : - Equipments - Reactor assembly - Electrodeposition cell - EXPERIMENTAL PROCEDURES : modifications of EPN resin for cathodic electrodeposition - Determination of Tertiary Amine Value (TAV) of the prepared adduct - Infrared spectroscopy - Cathodic Electrodeposition of films - Determination of degree of cure - Physical examination of film properties - Chemical resistance of films - Protection by films against corrosion - RESULTS AND DISCUSSION : Effect of molar ration of EPN to DEtOA on the characteristics of adduct - Effect of molar ration of EPN to DEA on the characteristics of adduct - Effect of reaction temperature and time on the characteristics of EPN-DEtOA (1:2 Moles) adducts - Curing characteristics of adduct films - Cathodic Electrodeposition of adduct films - Effect of deposition time on ED characteristics - Effect of applied voltage on ED characteristics - Effect of solution concentration - Effect of solution pH - kinetics of film growth during cathodic electrodeposition - Dry film thickness - Current density - Specific conductivity of the deposited film - Physical properties of films - Chemical resistance of films - Acid resistance - Methanol resistance - Corrosion resistance of films - CONCLUSIONS : Based on the findings of this work, following conclusions can be drawn - TECHNOLOGICAL CONTRIBUTION TO COATING INDUSTRY Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=12364 [article]

Réservation

Réserver ce document

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
001282	-	Périodique	Bibliothèque principale	Documentaires	Disponible

The role of surfactant on the film formation of latex polymers / P. Nagarajan in PAINTINDIA, Vol. XLVI, N° 2 (02/1996)

[article]  inPAINTINDIA > Vol. XLVI, N° 2 (02/1996) . - p. 19-24 Titre : The role of surfactant on the film formation of latex polymers Type de document : texte imprimé Auteurs : P. Nagarajan, Auteur ; C. K. Mital, Auteur ; M. K. Trivedi, Auteur Année de publication : 1996 Article en page(s) : p. 19-24 Note générale : Bibliogr. Langues : Anglais (eng) Tags : Latex  'Réseau  polymère  interpénétré'  'Méthacrylate  méthyle  polymère'  'Acrylate  butyle  'Méthacrylique  acide  'Système  ternaire'  'Formation  film'  'Agent  surface'  'Propriété  'Tension  superficielle' Index. décimale : 667.9 Revêtements et enduits Résumé : Two different latex interpenetrating polymer networks (LIPNs), comprising of polyacrylate (methyl methacrylate: n-butyl acrylate: methacrylic acid-43:57: 2.5) as seed and second polymer as polystyrene and polymethyl methacrylate, having a difference in hydrophilicity have been prepared. Surface tension measurements, were carried out to demonstrate the difference in adsorption equilibria of the anionic surfactant, sodium dodecyl sulphate on the different latex particles, with change in pH. the films were cast at different pHs, and it was found that the film of styrene based LIPN at a low pH (3.3), yielded translucent film while transparent films were also obtained from styrene based LIPN at a higher pH of 9, neutralized with NaOH. The higher strength of the latex films, obtained at the pH of 9 than those obtained at pH 3.3 of the styrene based LIPNs, indicates that the reduction in the polymer-water interfacial tension enhances the coalescence. It has been demonstrated clearly by the experimental evidence, that adsorption of surfactant on polymer, in styrene based latexes and the exudation of the surfactant in MMA based latexes, results in major difference in the optical clarity of the latex films. Note de contenu : - Preparation of LIPNs - Surface tension measurements - Transparency of the films - Tensile strength - Spectral measurements Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=13390 [article]

Réservation

Réserver ce document

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
006500	-	Périodique	Bibliothèque principale	Documentaires	Disponible

---

1 (1 - 2 / 2)