The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Wim J Van Ooij - One of the best experts on this subject based on the ideXlab platform.
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effects of addition of corrosion inhibitors to Silane films on the performance of aa2024 t3 in a 0 5 m nacl solution
Progress in Organic Coatings, 2005Co-Authors: Vignesh Palanivel, Yuhong Huang, Wim J Van OoijAbstract:Abstract Water-based organofunctional Silanes have been successfully used as an alternative to toxic chromate coatings for surface pre-treatment of metals and alloys. To further improve the performance of these Silane films, corrosion inhibitors were added to the Silane films and their corrosion properties investigated in 0.5 M NaCl solution. The inhibitors used were environmentally acceptable organic (tolyltriazole, benzotriazole) molecules and inorganic cerium salts. In the first part of the paper we discuss the inhibition efficiency of the individual inhibitor on the corrosion of AA2024-T3 alloy to understand the mechanisms of inhibition offered by these inhibitors. All of the above mentioned inhibitors effectively protected AA2024-T3 alloy against corrosion when immersed in a 0.5 M NaCl solution containing these inhibitors. In the second part of the paper the effects of the addition of inhibitors to Silane films was investigated. The results indicate that these inhibitors are slowly leached out and thus further improve the corrosion protection by Silane films and the inorganic inhibitors show promise of self-healing of defects.
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enhanced corrosion resistance of aa 2024 t3 and hot dip galvanized steel using a mixture of bis triethoxysilylpropyl tetrasulfide and bis trimethoxysilylpropyl amine
Electrochimica Acta, 2004Co-Authors: Danqing Zhu, Wim J Van OoijAbstract:Abstract The corrosion resistance of AA 2024-T3 and hot-dip galvanized steel (HDG) was studied after treatment with bis-[3-(triethoxysilyl)propyl]tetrasulfide (bis-sulfur Silane), bis-[trimethoxysilylpropyl]amine (bis-amino Silane), and their mixture. Electrochemical tests in neutral 0.6 M NaCl as well as scanning electronic microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDX) were performed. The results showed that: (1) hydrophilic bis-amino Silane did not offer good corrosion protection on either of the metals. This is probably because the bis-amino Silane film tends to be positively charged. This promotes ingress of anions like Cl − ions as well as water into the film by electrostatic attraction. As a result, corrosion readily proceeds at the interface. (2) Hydrophobic bis-sulfur Silane performed very well on AA 2024-T3, but failed on HDG. The failure here stems from non-uniform film coverage on HDG owing to an insufficient wetting of bis-sulfur Silane solution on the Zn oxide on HDG. Local corrosion initiates at defective sites which are poorly covered by the Silane film. (3) A bis-sulfur/bis-amino mixture at the ratio of 3/1 greatly enhanced the corrosion resistance of both AA 2024-T3 and HDG. This substantial improvement is achieved by selectively overcoming the major shortcomings of the individual Silanes.
Jukka Pekka Matinlinna - One of the best experts on this subject based on the ideXlab platform.
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Silane adhesion mechanism in dental applications and surface treatments a review
Dental Materials, 2018Co-Authors: Jukka Pekka Matinlinna, Christie Ying Kei Lung, James Kit Hon TsoiAbstract:Abstract Objective To give a current review of Silane adhesion chemistry, applications of Silane coupling agents and related surface pretreatment methods in contemporary dentistry. Methods Silane coupling agents are adhesion promoters to chemically unify dissimilar materials used in dentistry. Silanes are very effective in adhesion promotion between resin composites and silica-based or silica-coated indirect restorative materials. It is generally accepted that for non-silica-based restorations, surface pretreatment is a mandatory preliminary step to increase the silica content and then, with help of Silane, improve resin bonding. This review discusses the Silane-based adhesion chemistry, Silane applications in dentistry, surface pretreatment methods, and presents the recent development of Silane coupling agents. Results A Silane coupling agent is considered a reliable, good adhesion promoter to silica-based (or silica-coated) indirect restorations. Surface pre-treatment steps, e.g., acid etching for porcelain and tribo-chemical silica-coating for metal alloys, is used before silanization to attain strong, durable bonding of the substrate to resin composite. In clinical practice, however, the main problem of resin bonding using Silanes and other coupling agents is the weakening of the bond (degradation) in the wet oral environment over time. Significance A Silane coupling agent is a justified and popular adhesion promoter (adhesive primer) used in dentistry. The commercial available Silane coupling agents can fulfil the requirements in clinical practice for durable bonding. Development of new Silane coupling agents, their optimization, and surface treatment methods are in progress to address the long term resin bond durability and are highly important.
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aspects of Silane coupling agents and surface conditioning in dentistry an overview
Dental Materials, 2012Co-Authors: Christie Ying Kei Lung, Jukka Pekka MatinlinnaAbstract:Abstract Objectives To give an overview of aspects of Silane coupling agents and surface conditioning in dentistry. Methods Currently, Silane coupling agents are used as adhesion promoters. Silanes are effective in enhancing adhesion between resin composite and silica-based ceramics. They do not bond effectively to non-silica based dental restorative materials. Surface conditioning of non-silica based ceramics with silica coating improves the bonding. This current overview will focus on the Silane coupling agents: their properties, limitations in adhesion promotion and the clinical problems with the use of Silanes. It will also focus on the current surface conditioning methods as well as new surface conditioning techniques to enhance the bonding through conventional silanization approaches. Results Several surface conditioning methods are being used clinically to enhance the adhesion of resin composites to non-silica based restorative materials. Other approaches are under investigation. The clinical problem of using Silanes in adhesion promotion is the bond degradation over time in oral environment. Significance The current Silane coupling agents are not ideal. The current Silane coupling agents can fulfill the minimum requirements in clinical practice to enhance the bonding of resin composite to dental restorative materials. Developments of novel surface conditioning methods and Silane coupling agents are required to address the bond durability problem.
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The effect of three Silane coupling agents and their blends with a cross-linker Silane on bonding a bis-GMA resin to silicatized titanium (a novel Silane system)
Journal of Dentistry, 2006Co-Authors: Jukka Pekka Matinlinna, Lippo V J Lassila, Pekka K VallittuAbstract:Abstract Objectives Three activated organofunctional Silane coupling agents alone and blended with a non-functional cross-linker Silane were evaluated as adhesion promoters in an experiment where a bis-GMA (bis-phenol-A-diglycidyldimethacrylate) resin was bonded to silicatized titanium. The adhesive performances of the Silanes were assessed as shear bond strength values. Materials and methods 3-MethacryloyloxypropyltrimethoxySilane, N-[3-(trimethoxysilyl)propyl]ethylenediamine and [3-(triethoxysilyl)propyl]urea were prepared as 1.0 vol.% solutions in 95 vol.% ethanol. They were each also blended with 1.0 vol.% 1,2-bis-(triethoxysilyl)ethane solutions that were activated for 1 or 24 h. Titanium slides were cleaned, silicatized, distributed randomly to study groups and silanized with nine Silane solutions. After silanization experimental bis-GMA resin stubs were photo-polymerized and post-polymerized in a light-curing unit. The shear bond strength was measured as ‘dry samples’ and after thermo-cycling (6000 cycles at 5–55 °C). Results The type of Silane affected significantly the shear bond strength (p Conclusions Silanization with a blend of a functional Silane and a cross-linker Silane (a novel Silane system) might improve the hydrolytic stability of a siloxane film between silicatized titanium and a bis-GMA resin.
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an introduction to Silanes and their clinical applications in dentistry
International Journal of Prosthodontics, 2004Co-Authors: Jukka Pekka Matinlinna, Lippo V J Lassila, Mutlu Ozcan, Antti Yliurpo, Pekka K VallittuAbstract:Purpose: This overview presents a description of organofunctional trialkoxySilane coupling agents (Silanes), their chemistry, properties, use, and some of the main clinical experiences in dentistry. Materials and Methods: The main emphasis was on major dental journals that have been reviewed from 1958 up to the latest research news from 2002. A MEDLINE search with the key words “dental Silanes” was used. Special Silane literature and journals outside dentistry were also cited. Results: The main emphasis is on the use of Silanes in prosthetic and restorative dentistry. Clinical relevance was based mainly on either short- or long-term tests. The interpretation of various results is not given, mainly because of controversial observations that may be very difficult to explain. Nevertheless, the majority of the clinical results pointed to Silanes playing a significant role in the adhesion process. Silane reaction mechanisms were not entirely understood, and there exist several theories for bonding mechanisms for Silanes and substrates. Conclusion: Dental materials offer a continuously challenging forum for Silanes, and Silanes will play an essential role in material development. Publ. in: Int J Prosthodont 2004;17:155–164.
James Kit Hon Tsoi - One of the best experts on this subject based on the ideXlab platform.
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Silane adhesion mechanism in dental applications and surface treatments a review
Dental Materials, 2018Co-Authors: Jukka Pekka Matinlinna, Christie Ying Kei Lung, James Kit Hon TsoiAbstract:Abstract Objective To give a current review of Silane adhesion chemistry, applications of Silane coupling agents and related surface pretreatment methods in contemporary dentistry. Methods Silane coupling agents are adhesion promoters to chemically unify dissimilar materials used in dentistry. Silanes are very effective in adhesion promotion between resin composites and silica-based or silica-coated indirect restorative materials. It is generally accepted that for non-silica-based restorations, surface pretreatment is a mandatory preliminary step to increase the silica content and then, with help of Silane, improve resin bonding. This review discusses the Silane-based adhesion chemistry, Silane applications in dentistry, surface pretreatment methods, and presents the recent development of Silane coupling agents. Results A Silane coupling agent is considered a reliable, good adhesion promoter to silica-based (or silica-coated) indirect restorations. Surface pre-treatment steps, e.g., acid etching for porcelain and tribo-chemical silica-coating for metal alloys, is used before silanization to attain strong, durable bonding of the substrate to resin composite. In clinical practice, however, the main problem of resin bonding using Silanes and other coupling agents is the weakening of the bond (degradation) in the wet oral environment over time. Significance A Silane coupling agent is a justified and popular adhesion promoter (adhesive primer) used in dentistry. The commercial available Silane coupling agents can fulfil the requirements in clinical practice for durable bonding. Development of new Silane coupling agents, their optimization, and surface treatment methods are in progress to address the long term resin bond durability and are highly important.
Danqing Zhu - One of the best experts on this subject based on the ideXlab platform.
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enhanced corrosion resistance of aa 2024 t3 and hot dip galvanized steel using a mixture of bis triethoxysilylpropyl tetrasulfide and bis trimethoxysilylpropyl amine
Electrochimica Acta, 2004Co-Authors: Danqing Zhu, Wim J Van OoijAbstract:Abstract The corrosion resistance of AA 2024-T3 and hot-dip galvanized steel (HDG) was studied after treatment with bis-[3-(triethoxysilyl)propyl]tetrasulfide (bis-sulfur Silane), bis-[trimethoxysilylpropyl]amine (bis-amino Silane), and their mixture. Electrochemical tests in neutral 0.6 M NaCl as well as scanning electronic microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDX) were performed. The results showed that: (1) hydrophilic bis-amino Silane did not offer good corrosion protection on either of the metals. This is probably because the bis-amino Silane film tends to be positively charged. This promotes ingress of anions like Cl − ions as well as water into the film by electrostatic attraction. As a result, corrosion readily proceeds at the interface. (2) Hydrophobic bis-sulfur Silane performed very well on AA 2024-T3, but failed on HDG. The failure here stems from non-uniform film coverage on HDG owing to an insufficient wetting of bis-sulfur Silane solution on the Zn oxide on HDG. Local corrosion initiates at defective sites which are poorly covered by the Silane film. (3) A bis-sulfur/bis-amino mixture at the ratio of 3/1 greatly enhanced the corrosion resistance of both AA 2024-T3 and HDG. This substantial improvement is achieved by selectively overcoming the major shortcomings of the individual Silanes.
Ramanuj Narayan - One of the best experts on this subject based on the ideXlab platform.
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water based eco friendly epoxy Silane hybrid coating for enhanced corrosion protection adhesion on galvanized steel
Progress in Organic Coatings, 2016Co-Authors: Saheli Bera, Tapan Kumar Rout, G Udayabhanu, Ramanuj NarayanAbstract:Abstract In this current study, epoxy-Silane hybrid coatings were designed to investigate their anti-corrosion performance and adhesion on galvanized steel. Silanes with alkoxy group, epoxy group, amine group and thiol group were chosen to understand the role of functionalities in the performance of designed hybrid coatings. Moreover, the Silanes were added at three different concentrations into epoxy polymer to asses the effect of concentration on anti-corrosion and adhesion properties of the coating films. From scanning electron microscopic (SEM) images, we observed a uniform coating without any agglomeration of coating particles over galvanized steel substrates. The corrosion performance of casted and cured films was evaluated by using potentiodynamic polarization and AC impedance spectroscopy method. The physical properties, such as, thermal behavior and thermo-mechanical behavior were studied using differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) respectively. The adhesion strength between coating films and galvanized steel substrate was checked by ‘pull off’ adhesion test. It was found that due to the grafting of sol-gel coatings onto organic polymer backbone, the adhesion property and anti-corrosive performance has improved remarkably as compared to non-grafted epoxy polymer. It was observed that amino Silane showed superior performance compared to thiol Silane. The poor performance of thiol Silane grafted epoxy coating could be attributed to some chemical incompatibility of hydrophobic and non-polar sulfur Silane moiety and hydrophilic and polar waterborne epoxy polymer backbone. Addition of Silane by 1 wt% and 3 wt% into epoxy polymer backbone caused improvement in both anti corrosive property and adhesion strength but further increase of the Silane concentration to 5 wt% led to deterioration of protective property of the films. This drop in performance can be attributed to excessive consumption of epoxide groups in epoxy resin by amino and thiol functionalities present in Silane.
