[article]
| Titre : |
Polysilazanes : Binders that make a difference to surfaces |
| Type de document : |
texte imprimé |
| Auteurs : |
Yang Wang, Auteur ; Ralf Grottenmuller, Auteur ; Theresa Lorenz, Auteur |
| Année de publication : |
2019 |
| Article en page(s) : |
p. 38-45 |
| Note générale : |
Bibliogr. |
| Langues : |
Américain (ame) |
| Catégories : |
Anticorrosifs
Anticorrosion
Essais accélérés (technologie)
Liants
Polysilazanes
Résistance au rayonnement ultraviolet
Résistance aux conditions climatiques
Revêtements -- Additifs:Peinture -- Additifs
Revêtements anti-graffitis
Revêtements organiques
Stabilité thermique
|
| Index. décimale : |
667.9 Revêtements et enduits |
| Résumé : |
Polysilazanes are pre-ceramic polymers with a silicon-nitrogen backbone. In recent years they have developed as a high-performance binder in protective coatings for transportation vehicles, commercial and residential buildings, and industrial plants. This article reviews their structure-property relationship and highlights their performance in high-temperature, surface hardness, weathering and corrosion protection, and anti-graffiti applications. |
| Note de contenu : |
- Synthesis and process
- Heat stability
- Surface Hardness
- Weather and corrosion resistance
- Anti-graffiti properties
- Coating uniformity
- Fig. 1 : Polymer structures for PHPS and OPSZ, where R is H, CH3, CH=CH2, other alkyl, or aryl groups
- Fig. 2 : Polymer structures for PHPS and OPSZ, where R is H, CH3, CH=CH2, other alkyl, or aryl groups
- Fig. 3 : The two curing routes for OPSZ, where R1 and R2 are H, CH3, CH=CH2, other alkyl or aryl groups
- Fig. 4 : Thermal stability evaluation of polysilazanes. Panel A shows the results of TGA for polysilazanes and two commercial silicone resins. All materials were dried at 120°C for four hours before TGA to simulate the thermal stability of their coatings. Panel B shows a stainless-steel exhaust pipe coated with both PHPS and OPSZ-based TBC. Panel C compares the visual appearance of a coated and uncoated exhaust pipe after pyrolysis at 1000°C for one hour in air. Panels B and C were obtained from the Royal Society of Chemistry and Motz et al. at the University of Bayreuth with permission
- Fig. 5 : Characteristics of surface hardness for PHPS and OPSZ coatings. Panel A displays data of surface hardness for PHPS coatings on silicon substrates cured at different temperatures. These coatings have a film thickness of 1–1.2 μm. The hardness was measured via pencil hardness (in blue bars), Martens hardness (orange dots), and indentation resistance (black dots). The dots lines are guides for the eyes. Panel B shows a reference scale of pencil hardness, Martens hardness, and indentation resistance by using a bare glass and PMMA substrate. Panel C shows the anti-scratching property for a ∼3 μm thick OPSZ coating in clearcoat applications, and Panel D shows a similar performance for pigmented coatings. Both pigmented coatings have 17 wt% of pigment loading, a film thickness of 10–12 μm, and the right panel has 40 wt% polysilazane as a binder. Crockmeter test was performed by using an Atlas AATCC Crockmeter with 3M Wet-or-Dry 281Q rubbing cloth
- Fig. 6 : Panel A shows two steel substrates after a 10-day water condensation test at a constant humidity of 50%. They have an electrochemically deposited white basecoat with a film thickness of 15–20 μm that partially covers the substrates. The substrate on the left has a 3–4 μm thick polysilazane-based clearcoat, while the one on the right does not. Panel B shows a similar comparison of coated and uncoated areas on a steel substrate after three days of HCl vapor exposure at room temperature [a beaker of HCl solution (37 vol%) was placed in the test chamber]. The coating thickness is about 2 μm
- Fig. 7 : Panel A is a comparison of contact angle and surface energy for polysilazanes and three common binder materials, including nitrocellulose lacquer, acrylates, and polyurethanes. Also shown in Panel A is the value of the polar and dispersive component of surface energy, and surface energy is a sum of the polar and dispersive component. Panel B shows water drop shapes and contact angle measurements on a neat polysilazane coating and on a formulated polysilazane coating with other surface additives
- Fig. 8 : Panel A is a marker test to demonstrate the ink repellency and easy-to-clean properties for a polysilazane based clearcoat. The inset shows the results after cleaning with a dry towel. Panel B is the result of an anti-graffiti test performed on a similar coating according to ASTM D6578, where level 1—dry cloth, level 2—mild detergent solution, level 3— limonene-based cleaner, level 4—isopropanol, and level 5—methyl ethyl ketone, n.c.—not cleanable
- Fig. 9 : Three-dimensional surface morphology scans for a bare steel substrate (A), an OPSZ-based clearcoat on a steel panel (B), and a similar coating on a glass substrate (C). The polysilazane coating thickness is about 15 μm and 10 μm on the steel and the glass substrate, respectively
- Table 1 : DIN/EN/ISO tests that OPSZ-based coatingsz have successfully passed
- Table 2 : OPSZ coating performance before and after artificial weathering and UV stability test |
| En ligne : |
https://drive.google.com/file/d/1KuEizt3Csd6O2NpcxCtM9uj10C1GeiwC/view?usp=drive [...] |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=32737 |
in COATINGS TECH > Vol. 16, N° 6 (06/2019) . - p. 38-45
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