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COATINGS TECH . Vol. 18, N° 9New research on lowering VOCs as regulations tightenMention de date : 09/2021 Paru le : 08/11/2021 |
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Ajouter le résultat dans votre panierLow VOC topcoats using ultra high solids resins / Gautam Haldankar in COATINGS TECH, Vol. 18, N° 9 (09/2021)
[article]
Titre : Low VOC topcoats using ultra high solids resins Type de document : texte imprimé Auteurs : Gautam Haldankar, Auteur ; Niel Pfendt, Auteur Année de publication : 2021 Article en page(s) : p. 24-31 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Analyse thermomécanique dynamique
Evaluation
Formulation (Génie chimique)
Haut extrait sec
Polyacryliques
Polyols
Résistance chimique
Revêtements organiques
Solvants -- Suppression ou remplacement
VernisIndex. décimale : 667.9 Revêtements et enduits Résumé : In the North American coatings market, traditional solventborne resins are still used to a large extent, enabled by regulations that allow for the use of certain solvents exempt from restrictions placed on most volatile organic compounds (VOCs) in the United States. The future of the exempt status of parachlorobenzotrifluoride (PCBTF) and tertiary butyl acetate (TBAc) is a concern in certain districts of California, and other regions may follow suit.
Coating companies are ramping up their research efforts in formulating paint without exempt solvents. Researchers are opting to formulate with high solids resins.
High-performance acrylic polyols were studied to understand the effect of various resin parameters on coatings performance. A set of resins with 80-90% solids was tested in pigmented topcoat formulations.
These topcoats contained VOCs ranging from 200 to 250 g/L, without the use of exempt solvents. Various conventional and advanced film properties were evaluated, including weathering performance by xenon arc exposure, cure kinetics using infrared (IR) spectroscopy, and crosslink density by dynamic mechanical thermal analysis (DMTA).
Correlation was obtained between coatings performance properties and resin characteristics such as equivalent weight, glass transition temperature, etc. The understanding of structure property correlation offers tremendous value not only for North American coatings researchers but also to the global community.Note de contenu : - EXPERIMENTAL FINDINGS : Resin characteristics - Formulation and evaluation of clear films - Formulation of white topcoat - Evaluation of white topcoat
- RESULTS AND DISCUSSION : Disappearance of isocyanate by FTIR - Comparative film properties of white topcoat - Xenon weatherometer testing
- Table 1 : Characteristics of polyol resins
- Table 2 : Formulation guide to prepare clear film for DMTA analysis
- Table 3 : Formulation of white 2K topcoat with VOC ≤ 250 g/L
- Table 4 : Characteristics of formulated white topcoat
- Table 5 : Flexibility of the film after one month of cure
- Table 6 : Chemical resistance of ≤ 250 g/L white topcoatsEn ligne : https://drive.google.com/file/d/1OWpp2GZYlpsNJzc2GeK5yE0_Yyzz7Zcm/view?usp=share [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36422
in COATINGS TECH > Vol. 18, N° 9 (09/2021) . - p. 24-31[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 22992 - Périodique Bibliothèque principale Documentaires Disponible Novel hydrolytically stable silane additives for improving the performance of waterborne acrylic roof coatings / Jacob D. Shevrin in COATINGS TECH, Vol. 18, N° 9 (09/2021)
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Titre : Novel hydrolytically stable silane additives for improving the performance of waterborne acrylic roof coatings Type de document : texte imprimé Auteurs : Jacob D. Shevrin, Auteur Année de publication : 2021 Article en page(s) : p. 32-42 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Essais (technologie)
Formulation (Génie chimique)
Polyacryliques
Revêtements en phase aqueuse -- Additifs
Revêtements organiques
Silanes organofonctionnels
Stabilité hydrolytique
Toiture -- RevêtementsIndex. décimale : 667.9 Revêtements et enduits Résumé : As global environmental regulations continue to tighten restrictions on coatings containing volatile organic compounds (VOCs), the need for hydrolytically stable additives in waterborne coatings has never been greater.
Organofunctional alkoxysilanes are a class of widely used additives in the coatings industry. They act as a bridge between an organic coating and an inorganic substrate, providing adhesion promotion and other important performance improvements.
Given the high moisture sensitivity of organofunctional alkoxysilanes, most silane additives rapidly undergo condensation in waterborne coatings, leading to unworkable viscosities and gelling of the waterborne coatings within the first few weeks or months on the shelf. This has posed a significant barrier to using silane additives in waterborne coatings for all types of applications.
Two organofunctional silane additives that demonstrated positive hydrolytic stability over an extended period of time in waterborne acrylic roof coatings are investigated here.
Figure 1—From left to right : Epoxy-functional silane oligomer (VPS 4721) and amine-functional silane monomer (Dynasylan® 1505). Me = methyl, EtO = ethyl, R = epoxy-based moeity, X = epoxy-based moeity.These organofunctional silane additives include an epoxy-functional silane oligomer, VPS 4721, and an amine-functional silane monomer, Dynasylan® 1505.
The oligomeric structure of the epoxy-functional silane oligomer allows for slower hydrolysis and condensation rates in a waterborne system compared to a monomeric epoxy-functional silane (such as glycidoxypropyltrimethoxysilane).Note de contenu : - EXPERIMENTAL METHODS : Materials - Formulation preparation - Roofing membrane substrate preparation - Curing procedure - Testing procedures
- RESULTS AND DISCUSSION : Accelerated stability results - Water ponding resistance results - Dry and wet adhesion results on aged EPDM - Dry and wet adhesion results on aged asphalt - Elongation at break results - Tensile strength results - Dirt pickup resistance results - Surface hydrophobicity results - Accelerated weathering results
- Table 1 : Waterborne acrylic roof coating formulationEn ligne : https://drive.google.com/file/d/1IXOWtzMjf2ArkSL8TmK_VeLvLEcBQF9A/view?usp=share [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36423
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Code-barres Cote Support Localisation Section Disponibilité 22992 - Périodique Bibliothèque principale Documentaires Disponible The utilization of activated carbon as an antimicrobial agent against various pathogens for biomedical applications / Chloé Klusman in COATINGS TECH, Vol. 18, N° 9 (09/2021)
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Titre : The utilization of activated carbon as an antimicrobial agent against various pathogens for biomedical applications Type de document : texte imprimé Auteurs : Chloé Klusman, Auteur ; Zoe Gunter, Auteur ; Heather Broadhead, Auteur Année de publication : 2021 Article en page(s) : p. 44-47 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Antimicrobiens
Charbon actif
Escherichia coli
Staphylocoques
Technologie médicaleIndex. décimale : 667.9 Revêtements et enduits Résumé : Activated carbon (AC) has been utilized in several biomedical applications such as wound care and hemoperfusion, and in this work, experimental procedures were designed and carried out to better understand the effect of AC on bacteria, viruses, and parasites.
Antimicrobial properties of AC are relevant to the coatings industry because they can be incorporated into gel, liquid, or other coatings to impart antipathogenic properties. Possible biomedical applications include gels used for catheter tubing, drug capsule shells, and medical implants.
These experiments analyzed the ability of various sources of AC to exhibit antimicrobial properties by prohibiting the growth and propagation of pathogens. Wood, coconut, and coal-based AC were evaluated for activity against a series of bacterial dilutions with Escherichia coli (E. coli) and Staph aureus (S. aureus), a series of viral dilutions with T1 and Φ11 bacteriophages, and a series of parasitic dilutions with Euglena gracilis. Results were compared and analyzed using microscopy and other standard plating techniques.
Overall, the results collected from various trials displayed a significant reduction in the activity of the pathogens. Now that the concentration requirements and responsivity for the different pathogens are known, the potential mechanisms of interaction can be investigated.
In the presence of AC, the Euglena gracilis were observed to become immobile upon contact with AC. Unable to remain mobile, the Euglena expired. The immobilization of the parasite suggests that adsorption may play a key role in antipathogenic activity, although more studies are needed to be conclusive. Further research will be conducted to use AC in new biomedical applications, which will serve not only the biomedical industry but other research areas as well.Note de contenu : - Fig. 1 : Serial dilution of E. coli with various AC at the 10-5 dilution
- Fig. 2 : Serial dilution of S. aureus with various AC at the 10-7 dilution
- Fig. 3 : Euglena-as indicated by the red arrows-solution with 30 mg AC in deionized water at 400X magnification
- Fig. 4 : Euglena-as indicated by the red arrows-solution with 15 mg AC in deionized water at 400X magnificationEn ligne : https://drive.google.com/file/d/1JobmmaJLojonEkPT9eg2t4Vr-SZPC9-V/view?usp=share [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36424
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