Academic literature on the topic 'Silani'
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Journal articles on the topic "Silani"
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Ragaišytė, Ieva, Mindaugas Daukšys, and Albertas Klovas. "PROPERTIES OF HARDENED CEMENT PASTE DEPENDING ON SILANE BASED CHEMICAL ADMIXTURES / CHEMINIŲ PRIEDŲ SILANŲ PAGRINDU ĮTAKA CEMENTINIO AKMENS SAVYBĖMS." Engineering Structures and Technologies 4, no. 1 (April 18, 2012): 29–36. http://dx.doi.org/10.3846/2029882x.2012.677409.
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The article focuses on the influence of water repellent, silane based concrete admixtures on the physical, mechanical and porosity properties of hardened cement paste. To obtain the expected results, six compositions of cement slurries were designed changing the amount and type of the silane based chemical admixture. In order to obtain technological, physical and mechanical properties of cement (slurry) stone, the following experiments, including a test on the flow characteristics of cement slurries, a test on compression and bending strength as well as the analysis of porosity and resistance to frost were accomplished. On the basis of the achieved results and using a different amount and type of silane based chemical admixtures, the flow characteristics of cement slurry has increased up to 1,47 times in respect to the control specimen. On the other hand, when using the above introduced silane based chemical admixtures, the obtained results show a decrease in the density and strength of compression and bending. By adding chemical admixture “WACKER BS 1701” 0,2% and taking into account the amount of cement, a decrease in density goes up to 2,4%. The most noticeable decrease in bending strength (26%) is obtained by using WACKER BS SMK 2101 (0,1% in respect to the amount of cement). In addition, the biggest decrease in compression strength (34,6%), considering the control specimen, can be noticed when using SILRES BS 290 (0,2%) as a silane based chemical admixture. Water absorption of the control specimen with no silane based chemical admixtures is very similar to those containing them (vary around 1). The properties of porosity (opened and closed) are also very close and vary around 2% at the maximum. The indicator of medium pore size-λ shows that the control specimen include large pores (λ = 7,92). In most cases, by using the silane based chemical admixture, minor pores are obtained (λ = 0,94 – 3,66). The results received following 100 cycles of freezing-thaw show that all specimens have passed the test. Their surfaces did not contain any cracking. Santrauka Straipsnyje nagrinėjama cheminių priedų silanų/siloksanų pagrindu įtaka cementinio akmens fizikinėms ir mechaninėms savybėms bei poringumui. Tyrimams buvo paruoštos šešios cemento tešlos, naudojant skirtingos koncentracijos silanų/siloksanų pagrindu pagamintus cheminius priedus. Tyrimo metu nustatytas cemento tešlos sklidumas, cementinio akmens tankis, lenkimo ir gniuždymo stipriai, poringumo parametrai bei atsparumas šalčiui. Nustatyta, kad naudojant skirtingos koncentracijos silanų/siloksanų pagrindu pagamintus cheminius priedus, cemento tešlos sklidumas padidėjo iki 46,3%, lyginant su kontroline tešla. Cementinio akmens tankis sumažėjo iki 2,4%, lenkimo stipris – iki 21,0%, gniuždymo stipris – iki 34,6%, lyginant su kontroliniu bandiniu be silanų/siloksanų pagrindu pagamintų priedų. Cementinio akmens be cheminių priedų silanų/siloksanų pagrindu vandens įgėris (12,16%), atviras ir uždaras poringumai yra panašūs kaip ir cementinio akmens su cheminiais priedais silanų/siloksanų pagrindu. Cementinio akmens bandiniai išlaikė 100 užšaldymo ir atšildymo ciklų atsparumo šalčiui bandymą.
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Rosatto, Camila Maria Peres de, Marina Guimarães Roscoe, Veridiana Resende Novais, Murilo de Sousa Menezes, and Carlos José Soares. "Effect of Silane Type and Air-Drying Temperature on Bonding Fiber Post to Composite Core and Resin Cement." Brazilian Dental Journal 25, no. 3 (July 2014): 217–24. http://dx.doi.org/10.1590/0103-6440201300005.
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This study evaluated the influence of silane type and temperature of silane application on push-out bond strength between fiberglass posts with composite resin core and resin cement. One hundred and sixty fiberglass posts (Exacto, Angelus) had the surface treated with hydrogen peroxide 24%. Posts were divided in 8 groups according to two study factors: air-drying temperature after silane application (room temperature and 60 ºC) and silane type: three pre-hydrolyzed - Silano (Angelus), Prosil (FGM), RelyX Ceramic Primer (3M ESPE) and one two-component silane - Silane Coupling Agent (Dentsply). The posts (n=10) for testing the bond strength between post and composite core were centered on a cylindrical plastic matrix and composite resin (Filtek Z250 XT, 3M ESPE) that was incrementally inserted and photoactivated. Eighty bovine incisor roots (n=10) were prepared for testing the bond strength between post and resin cement (RelyX U100, 3M ESPE) and received the fiberglass posts. Push-out test was used to measure the bond strength. Data were analyzed by two-way ANOVA followed by Tukey's test (a=0.05). ANOVA revealed that temperature and silane had no influence on bond strength between composite core and post. However, for bond strength between post and resin cement, the temperature increase resulted in a better performance for Silane Coupling Agent, Silano and RelyX Ceramic Primer. At room temperature Silane Coupling Agent showed the lowest bond strength. Effect of the warm air-drying is dependent on the silane composition. In conclusion, the use of silane is influenced by wettability of resinous materials and pre-hydrolyzed silanes are more stable compared with the two-bottle silane.
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CHRUSCIEL, JERZY, ELZBIETA LESNIAK, and MARZENA FEJDYS. "Carbofunctional silanes and polysiloxanes. Part I. Applications of carbofunctional silanes." Polimery 53, no. 10 (October 2008): 709–16. http://dx.doi.org/10.14314/polimery.2008.709.
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Savitri, Savitri, Evi Triwulandari, Agus Haryono, and O. A. Syahputra. "PENGARUH SENYAWA SILAN TERHADAP SIFAT MEKANIK MATERIAL PELAPIS PADUAN HIBRID EPOKSI TERMODIFIKASI POLIURETAN." Jurnal Kimia Terapan Indonesia 17, no. 1 (December 10, 2015): 15–26. http://dx.doi.org/10.14203/jkti.v17i1.19.
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Preparation of hybrid coating material from modified epoxy polyurethane (ETP) and silan (Si) has been done. Epoxy and polyurethane were modified with silan using γ-Glisidoksil propil trimetoksisilan (GPTMS) and γ-aminopropyl triethoxysilane (γ-APS) and also dibutyltindilaurate (DBTL) as catalyst. Fourier Transform Infrared (FTIR) characterization indicated that the hybrid coating material has been formed. The results of the analysis of NCO percent and conversion rate of isocyanates (α) also verified that the ETP-Si hybrid coatings have been formed. The addition 30% of silane as Si-O group indicated the rest of NCO percent was the lowest for hybrid coating material with polyurethane concentration of 5% and 10. The composition of ETP5% - Si 30% was the optimum composition from the ETP-Si hybrid coating material based on the mechanical analysis.Key words: hybrid coating, polyurethane, epoxy, silane, ETP – Si
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Novais, Veridiana Resende, Paulo Cézar Simamotos Júnior, Regina Maria Puppin Rontani, Lourenço Correr-Sobrinho, and Carlos José Soares. "Bond strength between fiber posts and composite resin core: influence of temperature on silane coupling agents." Brazilian Dental Journal 23, no. 1 (2012): 08–14. http://dx.doi.org/10.1590/s0103-64402012000100002.
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This study evaluated the effect of air drying temperature and different silane coupling agents on the bond strength between glass fiber posts and composite resin core. The post surface was cleaned with alcohol and treated with different silane coupling agents, being three prehydrolyzed silanes [Silano (Angelus), Prosil (FGM), RelyX Ceramic Primer (3M ESPE)] and one two-component silane [Silane Coupling Agent (Dentsply)]. Two post-silanization air drying temperatures, 23ºC and 60ºC, were applied. A cylindrical plastic matrix was placed around the silanized post and filled with composite resin. Each bonded post provided 7 slices for push-out testing. Each slice was loaded to failure under compression at a cross-head speed of 0.5 mm/min. Data were analyzed by two-way ANOVA and Scott-Knott tests (α=0.05). Dunnett's test was used to compare the mean of the control group with that of each experimental group. Scanning electron microscopy (SEM) was used to evaluate the interface of the fractured slices. For the 23ºC air drying temperature, the use of RelyX Ceramic Primer resulted in significantly lower bond strength than the other silane coupling agents, while the bond strength with Silane Coupling Agent was the highest of all groups. Only with Silane Coupling Agent, the bond strength for the 23ºC air drying temperature was significantly higher than that for 60ºC air drying. In conclusion, the use of warm air drying after silane application produced no increase in the bond strength between the fiber-reinforced composite post and the composite core. The two-component silane produced higher bond strength than all prehydrolyzed silanes when it was used with air drying at room temperature.
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Zanelli, Wilian Segatto, Mariana Dias Flor-Ribeiro, Rodrigo Barros Esteves, Luís Roberto Marcondes Martins, Flávio Henrique Baggio Aguiar, and Giselle Maria Marchi. "Repair Adhesive Strength of Conventional and Bulk Fill Resins Using Different Bonding Techniques." Journal of Health Sciences 22, no. 3 (September 20, 2021): 185–90. http://dx.doi.org/10.17921/2447-8938.2021v22n3p185-190.
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AbstractThis research aimed to evaluate the bond strength by micro tensile strength (µTBS), elastic modulus (EM) and flexural strength (FS) by the three-point test using three types of composite resins: Charisma Diamond, Filtek Z350 and Tetric N-Ceram Bulk Fill; and three adhesion techniques: adhesive, silane, silane and adhesive. The combinations of each resin with the adhesive technique resulted in nine groups (n = 12). Initially, with the composites, EM and FS tests were performed. Sequentially, each fragment was repaired with the different adhesive systems. All samples were subjected to µTBS testing on a universal assay machine. Data were subjected to the normality test and the parametric ANOVA test. Charisma resin showed the highest values in EM and RF compared to the other composite resins (p <0.05). The highest µTBS value was for silane + adhesive repaired Charisma resin. The lowest µTBS values were in Bulk Fill resin, regardless of adhesive system. The EM and FS results showed that Filtek Z350 resins had the best results, while bulk fill resins had lower results. It was concluded that Charisma and Filtek Z350 resins presented better results. However, in the bulk fill group, the lowest mean values of µTBS, FS and EM were obtained, as well as the lowest value in EM.Keywords: Composite Resins. Adhesives. Flexural Strength.ResumoEsta pesquisa teve como objetivo avaliar a resistência de união (RU) por resistência à microtração, módulo de elasticidade (ME) e resistência à flexão (RF) pelo teste de três pontos, utilizando três tipos de resinas compostas: Charisma Diamond, Filtek Z350 e Tetric N-Ceram Bulk Fill; e três técnicas de adesão: adesivo, silano, silano e adesivo. As combinações de cada resina com a técnica adesiva resultaram nove grupos (n= 12). Inicialmente, com os compósitos foram realizados testes de ME e RF. Sequencialmente, cada fragmento foi reparado com os diferentes sistemas adesivos. Todas as amostras foram submetidas ao teste de RU por microtração em uma máquina de ensaio universal. Os dados foram submetidos ao teste de normalidade e ao teste paramétrico ANOVA. A resina Charisma apresentou os maiores valores no ME e RF em relação às demais resinas compostas (p <0,05). O maior valor de RU foi para a resina Charisma reparada com silano + adesivo. Os menores valores de RU foram na resina Bulk Fill, independentemente do sistema adesivo. Os resultados no ME e RF mostraram que as resinas Filtek Z350 obtiveram os melhores resultados, enquanto as resinas bulk fill obtiveram resultados inferiores. Conclui-se que as resinas Charisma e Filtek Z350 apresentaram melhores resultados. Entretanto, no grupo de bulk fill obteve se as menores médias de RU, RF e ME, bem como o menor valor no ME.Palavras-chave: Resinas Compostas. Adesivos. Resistência à Flexão.
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Schenzel, Karla, Karl Hassler, and Günther Bauer. "Schwingungsspektren und Normalkoordinatenanalysen sterisch überladener Silane: Tetrakis(trimethylsilyl)silan und Hexakis(trimethylsilyl)disilan." Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 53, no. 14 (December 1997): 2435–43. http://dx.doi.org/10.1016/s1386-1425(97)00225-4.
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Haase, Martin, and Uwe Klingebiel. "Tris(silyl)silyl-chlorsilane und P-halogenierte Silylphosphane / Tris(silyl)silyl-chlorosilanes and P-Halogenated Silylphosphanes." Zeitschrift für Naturforschung B 41, no. 6 (June 1, 1986): 697–701. http://dx.doi.org/10.1515/znb-1986-0606.
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Lithium-tris(trimethylsilyl)silan reacts with chlorosilanes to give thermally stable compounds (1−3). The chlorination of 3 leads to the formation of the silane (Me3Si)3SiSi(Cl)(CMe3)2 4. The reaction of tetramethylpiperidinodihalogenophosphanes with (Me3Si)3SiSi(Cl)(Cme3)2 results in thermally stable compounds (Me3Si)3Si−P(Hal)N(CMe2)2(CH2)3, Hal = F (5). Cl (6), (Me3Si)3Si−P(Cl)N(CHMe2)2 (7) undergoes thermaly rearrangement via a silicon-chlorine exchange reaction to give (Me3Si)2Si(Cl)−P(SiMe3)N(CHMe2)2 (8). A byproduct − besides cyclic phosphanes - is the silylamine (Me3Si)2Si(Cl)N(CHMe2) (9). The formation of (9) can be explained via the elimination of the phosphinidene Me3SiP.
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Nyman, B. "Schutzbehandlung von Beton mit Silan- und Siloxanpräparaten / Protective Treatment of Concrete with Silane or Siloxane." Restoration of Buildings and Monuments 5, no. 3 (June 1, 1999): 307–10. http://dx.doi.org/10.1515/rbm-1999-5377.
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Abstract By means of laboratory experiments it is shown that the penetration depth of a treatment of concrete with Silane depends strongly on the duration of suction and on the moisture content of the concrete. The necessary duration of suction can be estimated for any required penetration depth.
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Czarnecki, L., and B. Chmielewska. "Bruchverhalten und Fraktographie eines Silan modifizierten Kunstharzmörtels / Fracture and Fractography of Silane Modified Resin Mortars." Restoration of Buildings and Monuments 9, no. 6 (December 1, 2003): 603–18. http://dx.doi.org/10.1515/rbm-2003-5806.
Full textDissertations / Theses on the topic "Silani"
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IMIETE, IIKPOEMUGH ELO. "Light Weight Polysaccharides as biofillers for Elastomeric Compounds." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2021. http://hdl.handle.net/10281/313695.
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I pneumatici sono realizzati aggiungendo riempitivi alla matrice polimerica. Insieme ad altri additivi, le mescole per pneumatici vengono polimerizzate e modellate. I riempitivi convenzionali utilizzati nel processo sono nerofumo e silice. A causa delle preoccupazioni ambientali associate all'uso di questi riempitivi, in questo lavoro sono stati esplorati polisaccaridi leggeri derivati da fonti biologiche come possibile sostituzione. I riempitivi utilizzati in questo progetto erano nanocristalli di cellulosa e alfa 1,3 glucano. La loro chimica superficiale è simile a quella delle cariche di silice aventi abbondanti gruppi idrossilici superficiali. Questi bio-riempitivi sono idrofili e non compatibili con la matrice polimerica idrofobica come la gomma naturale. A questo proposito, sono stati modificati per essere compatibili con la matrice polimerica.
Per ottenere questa modifica, sono stati impiegati due silani: TESPD, APS essendo silani alifatici e SID, SIB essendo silani ciclici. Tutti i composti sono stati confrontati con i composti di silice come riferimento. I risultati ottenuti con queste cariche hanno mostrato che i silani APS favoriscono una vulcanizzazione molto rapida e aumentano la densità di reticolazione. Con questo silano, è stato ottenuto un modulo di stoccaggio più elevato e le proprietà erano migliori rispetto ai composti di silice di riferimento. Lo svantaggio riscontrato con APS è il fatto che una grande quantità di silano influisce sulle proprietà di trazione. Il meccanismo di reazione osservato per i composti TESPD rivela che il modulo di conservazione dei composti con questo silano potrebbe non essere paragonabile a quello di APS, ma le proprietà di trazione erano notevolmente superiori. La decisione su quali silani da utilizzare sarebbe quindi collegata alle proprietà attese che è di interesse.
Quando sono stati esplorati i silani ciclici, la loro natura reattiva ha reso la vulcanizzazione veloce. Molto interessante il rinforzo delle varie mescole. Tuttavia, è stato osservato che a un basso carico di silano compreso tra il 2-5%, le proprietà rimangono pressoché le stesse anche quando le quantità di silano sono state aumentate fino al 12%. Infatti, la quantità di silani ciclici superiore al 5% rendeva il materiale fragile e produceva proprietà di trazione molto inferiori. Si consiglia quindi di preparare la carica polisaccaridica con bassissime quantità di silani ciclici.
Le modifiche con i silani sono state esplorate in quanto è ampiamente utilizzato nell'industria dei pneumatici. In alternativa, è stata studiata anche una modifica enzimatica verde che utilizza le lipasi come catalizzatore. La procedura sviluppata in questo lavoro è stata semplificata con la possibilità di recuperare tutto il filler utilizzato nella reazione e il riutilizzo di altre specie reagenti. Il concetto in questa modifica era quello di innestare porzioni che possono servire per idrofobizzare la superficie e successivamente promuovere una reticolazione diretta tra il riempitivo e la gomma. Il nanocristallo di cellulosa è stato il riempitivo di questa modifica e sulla superficie sono stati innestati gruppi acetile e metacrilato. Quando i composti sono stati preparati con il CNC modificato, le proprietà erano molto interessanti. In effetti, erano migliori della silice di riferimento. I risultati ottenuti in questo processo sono molto promettenti, soprattutto se si considera il futuro dell'industria dei pneumatici.
Il glucano è un nuovo concorrente nel mondo dei biofiller per l'industria dei pneumatici, è ancora in fase di studio per accertarne l'idoneità. I composti realizzati con glucano utilizzando silani hanno mostrato che alcuni aspetti delle proprietà sono inferiori alla silice di riferimento. In termini di composti verdi e proprietà di vulcanizzazione, era relativamente migliore del composto di silice.Tires are made by adding fillers to polymeric matrix. Alongside other additives, the tire compounds are cured and shaped. The conventional fillers used in the process is carbon black and silica. Owing to the environmental concerns associated with the use of these fillers, lightweight polysaccharides derived from bio sources were explored in this work as possible replacement. The fillers that were used in this project were cellulose nanocrystals and alpha 1,3 glucan. Their surface chemistry is like that of silica fillers having abundant surface hydroxyl groups. These bio fillers are hydrophilic and not compatible with hydrophobic polymer matrix such as natural rubber. In this regard, they were modified to be compatible with the polymeric matrix. To achieve this modification, two silanes were employed: TESPD, APS being aliphatic silanes and SID, SIB being cyclic silanes. All the compounds were compared with silica compounds as reference. The results obtained with these fillers showed that the APS silanes promote very fast vulcanization and increases the crosslinking density. With this silane, a higher storage modulus was achieved, and properties were better than the reference silica compounds. The drawback that was experience with APS is the fact that large amount of the silane affects the tensile properties. The reaction mechanism observed for TESPD compounds reveals that the storage modulus of the compounds with this silane may not be comparable to that of APS but the tensile properties were remarkably higher. Deciding on which silanes to be used would therefore connect with the expected properties that is of interest. When the cyclic silanes were explored, their reactive nature made the vulcanization to be fast. The reinforcement of the various compounds was very interesting. However, it was observed that at low silane loading between 2-5%, the properties remain fairly the same even when the silane amounts were increased up to 12%. In fact, the cyclic silanes amount exceeding 5% made the material brittle and resulted in very inferior tensile properties. It is therefore advisable to prepare the polysaccharides filler with very low amount of cyclic silanes. The modifications with silanes were explored as it is heavily used in the tire industry. Alternatively, a green enzymatic modification using lipases as catalyst was also investigated. The procedure developed in this work was simplified with the possibility of recovering all the filler used in the reaction and the reuse of other reacting species. The concept in this modification was to graft moieties that can serve to hydrophobized the surface and subsequently promote a direct crosslinking between the filler and rubber. The cellulose nanocrystal was the filler for this modification and acetyl and methacrylate groups were grafted on the surface. When compounds were prepared with the modified CNC, the properties were very interesting. In fact, they were better than the reference silica. The results obtained in this process are very promising especially when the future of the tire industry is considered. Much attention was given to cellulose nanocrystals compared to alpha 1,3 glucan. Although glucan is a new entrant into the biofiller world for the tire industry, it is still being studied to ascertain their suitability. The compounds made with glucan using silanes showed that some aspects of the properties are lower that the reference silica. In terms of the green compounds and vulcanization properties, it was relatively better than silica compound. But when glucan compounds were vulcanized, the reinforcements and tensile properties were observed to be lower than silica compounds. It is obvious that more treatment, processing methods and the use of vast alternative modification strategy is needed to prepare glucan for improved properties and possible use in tire compounds.
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Oliveira, Aline Cristina Maia de [UNESP]. "Avaliação dos parâmetros de processo de reticulação do polietileno de baixa densidade." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/94445.
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O presente trabalho aborda as condições de reticulação do polímero termoplástico polietileno e, para isso, foram avaliadas diferentes temperaturas de processo (60 e 90°C), bem como diferentes tempos de permanência em imersão em banho termostatizado (1, 3, 6 e 9 horas). Esta avaliação foi realizada a partir dos ensaios de teores de gel e fator de uptake, de massa específica, de calorimetria exploratória diferencial (DSC), de análise termogravimétrica (TGA), de espectrofotometria no infravermelho com transformada de Fourier (FT-IR) e de ensaios de tração. Desta forma, o grau de reticulação do polietileno de baixa densidade reticulado em água, foi correlacionado com sua morfologia, com seu desempenho térmico e mecânico. Os resultados mostraram que o teor de gel do polietileno reticulado aumentou com o aumento da temperatura e do tempo de exposição desta matriz polimérica em água, sendo que, este aumento ocorreu de forma significativa até 3 horas de exposição, não sendo observados ganhos significativos na formação de ligações cruzadas após este período
The present work deals with the crosslink conditions of polyethylene polymer using different process temperatures (60 and 90°C). For this different water immersion times in thermostated bath (1, 3, 6 and 9 hours) have been analyzed by using gel content and uptake factor, density tests, dynamic scanning calorimetric analyses (DSC), thermogravimetric analysis (TGA), infrared spectroscopy (FT-IR) and tensile tests. This way, it was evaluated the degree of crosslinking of low density polyethylene crosslinked into water, and these parameters were correlated with the morphology and its thermal and mechanical performance. According to found results, it was observed that the gel content of polyethylene crosslinked increased with increasing of exposition temperature and time of this polymeric matrix in water, therefore, this increase was significantly up to 3 hours of exposition, not being observed significant gains in crosslinking density after this time
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Oliveira, Aline Cristina Maia de. "Avaliação dos parâmetros de processo de reticulação do polietileno de baixa densidade /." Guaratinguetá : [s.n.], 2011. http://hdl.handle.net/11449/94445.
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Resumo: O presente trabalho aborda as condições de reticulação do polímero termoplástico polietileno e, para isso, foram avaliadas diferentes temperaturas de processo (60 e 90°C), bem como diferentes tempos de permanência em imersão em banho termostatizado (1, 3, 6 e 9 horas). Esta avaliação foi realizada a partir dos ensaios de teores de gel e fator de uptake, de massa específica, de calorimetria exploratória diferencial (DSC), de análise termogravimétrica (TGA), de espectrofotometria no infravermelho com transformada de Fourier (FT-IR) e de ensaios de tração. Desta forma, o grau de reticulação do polietileno de baixa densidade reticulado em água, foi correlacionado com sua morfologia, com seu desempenho térmico e mecânico. Os resultados mostraram que o teor de gel do polietileno reticulado aumentou com o aumento da temperatura e do tempo de exposição desta matriz polimérica em água, sendo que, este aumento ocorreu de forma significativa até 3 horas de exposição, não sendo observados ganhos significativos na formação de ligações cruzadas após este períodoAbstract: The present work deals with the crosslink conditions of polyethylene polymer using different process temperatures (60 and 90°C). For this different water immersion times in thermostated bath (1, 3, 6 and 9 hours) have been analyzed by using gel content and uptake factor, density tests, dynamic scanning calorimetric analyses (DSC), thermogravimetric analysis (TGA), infrared spectroscopy (FT-IR) and tensile tests. This way, it was evaluated the degree of crosslinking of low density polyethylene crosslinked into water, and these parameters were correlated with the morphology and its thermal and mechanical performance. According to found results, it was observed that the gel content of polyethylene crosslinked increased with increasing of exposition temperature and time of this polymeric matrix in water, therefore, this increase was significantly up to 3 hours of exposition, not being observed significant gains in crosslinking density after this time
Orientador: Edson Cocchieri Botelho
Coorientador: Antonio Fernando Branco Costa
Banca: Luiz Claudio Pardini
Banca: Michelle Leali Costa
Mestre
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Niedermayer, Wolfgang. "Auf dem Wege zu einem Disilin RSi≡SiR Supersilylierte Silane, Silanide, Silylene, Disilene." Diss., lmu, 2000. http://nbn-resolving.de/urn:nbn:de:bvb:19-2914.
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Garcia, Bruno Pienis. "Associação de taninos e silano na passivação de aço galvanizado." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/165150.
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A proteção contra a corrosão do aço galvanizado com um tratamento via cromatização, apesar de apresentar desempenho superior à outras alternativas, gera efluentes tóxicos ao meio ambiente e em especial aos seres humanos. Dentre as alternativas apresentadas até o presente momento, que incluem diversos tipos de tratamentos para esse substrato, um deles é o revestimento com silanos. Apesar desse revestimento ter um satisfatório desempenho, vem se utilizando incorporações em seu preparo, para se potencializar seu desempenho. A incorporação escolhida nesse trabalho foi a do tanino, um inibidor de corrosão natural, extraído de vegetais. O objetivo desse trabalho é avaliar um revestimento do silano Ortossilicato de tetraetila (TEOS) junto de um tanino para o aço galvanizado destinado a aplicações onde não há pintura. Essa sinergia deve proteger a superfície até que o zinco consiga de forma natural desenvolver sua pátina protetora, formando uma barreira entre substrato e eletrólito. Foram revestidas chapas de aço galvanizado com períodos de imersão que variaram entre 2 e 10 minutos, com soluções na concentração de tanino de 2g/L e 10g/L com diferentes valores de pH, em uma solução previamente preparada de TEOS em concentração de 2%, água 49% e etanol 49%. Realizou-se análise comparativa entre os diferentes parâmetros de tratamento proposto neste trabalho com aço galvanizado somente desengraxado e aço galvanizado cromatizado nas seguintes técnicas: espectroscopia de impedância eletroquímica, polarização potenciodinâmica, microscopia eletrônica de varredura acoplada a espectroscopia de energia dispersiva, e ensaios de corrosão acelerada em câmara úmida e névoa salina. Os resultados apresentados indicam que diferentes concentrações de tanino e tempos de imersão não são significativos para causar diferenças relevantes entre os desempenhos e que os substratos tratados demonstraram um desempenho superior comparado às amostras que não tinham nenhum tipo de tratamento e inferiores às amostras cromatizadas.The corrosion protection of galvanized steel with a chromatized treatment, despite superior performance to other alternatives, generates effluents toxic to the environment and especially to humans. Among the alternatives presented to date, which include several types of treatments for this substrate, one of them is the coating with silanes. Although this coating has a satisfactory performance, it has been using incorporations in its preparation, to enhance its performance. The incorporation chosen in this work was that of tannin, a natural corrosion inhibitor, extracted from plants. The objective of this work is to evaluate a coating of silane tetraethyl orthosilicate (TEOS) with tannin for galvanized steel, for applications where there is no paint. This synergy should protect the surface until zinc can naturally develop its protective patina, forming a barrier between substrate and electrolyte. Galvanized steel plates were coated with immersion times ranging from 2 to 10 minutes, with solutions at tannin concentration of 2 g/L and 10 g/L with different pH values, in a previously prepared solution of TEOS at a concentration of 2% , 49% of water and 49% of ethanol. A comparative analysis was performed between the different treatment parameters proposed in this work with galvanized steel only degreased and galvanized steel chromatized in the following techniques: electrochemical impedance spectroscopy (EIE), potentiodynamic polarization, scanning electron microscopy coupled to dispersive energy spectroscopy, and corrosion tests accelerated in humid chamber and saline mist. The results indicated that different concentrations of tannin and immersion times are not significant to cause relevant differences between the performances and that the substrates demonstrated superior performance compared to the samples that had no type of treatment, and inferior to the samples chromatized.
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Murillo, Gomez Fabian de Jesus 1987. "Avaliação da união cerâmica-vítrea/cimento-resinoso usando diferentes soluções contendo silano = Evaluation of glass-ceramic/resin-cement interface using different silane-containing solutions." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288150.
Full textAbstract:
Orientador: Mario Fernando de GoesDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: O objetivo deste estudo foi avaliar a interação de diferentes soluções contendo silano, com cerâmica vítrea e cimentos resinosos por meio da resistência de união por microcisalhamento e avaliação morfológica da fratura. Este estudo foi separado em dois capítulos. No capítulo 1 foi verificada a influência de quatro soluções contendo silano (solução convencional, solução convencional seguida da aplicação de um sistema adesivo convencional, sistema adesivo universal contendo silano e um primer universal para materiais cerâmicos contendo silano) e a influência do uso ou não do condicionamento prévio da cerâmica com ácido fluorídrico na resistência de união entre uma cerâmica vítrea e um cimento resinoso convencional, após 24h. A análise morfológica da fratura foi avaliada com microscópio eletrônico de varredura. Todos os dados foram submetidos à análise de variância a dois fatores e teste de Tukey (?=0.05). Os resultados mostraram que o condicionamento prévio da cerâmica com ácido fluorídrico foi um fator determinante na obtenção de valores estatisticamente significativos na resistência de união entre ela e o cimento resinoso. A solução de silano convencional foi o único tratamento que proporcionou valores significativamente maiores de resistência de união sem a aplicação do condicionamento prévio na cerâmica vítrea. Todas as soluções proporcionaram resistência de união estatisticamente superior quando o ácido fluorídrico foi usado previamente em relação ao grupo de cerâmicas só jateadas com óxido de alumínio. Os valores foram diferentes estatisticamente entre as soluções, sendo a solução convencional de silano a mais efetiva. Padrão de fratura coesiva no cimento foi associado com valores maiores, enquanto que falha adesiva foi associada com menor resistência de união. No capítulo 2, o objetivo foi avaliar a interação das mesmas soluções contendo silano com cinco cimentos resinosos, três convencionais (Rely X Ultimate, Rely X ARC e Variolink II) e dois autoadesivos (Bifix e Rely X Unicem 2). A resistência de união por microcisalhamento e o tipo de fratura foram avaliados. Os valores foram submetidos à análise estatística a dois fatores e ao teste de Tukey (?=0.05). Os resultados mostraram que a resistência de união foi maior quando a cerâmica foi tratada com a solução convencional de silano para todos os cimentos. A maioria dos cimentos apresentou resistência de união sem diferença estatística quando usados junto com o sistema adesivo universal e o primer cerâmico, exceto para o Bifix e Rely X ARC. Nas fotografias em MEV observaram-se áreas de polimerização incompleta nos casos do Bifix e Rely X ARC. Os grupos com melhor resistência de união apresentaram maior prevalência de fratura coesiva no cimento, enquanto que os grupos com menores valores de resistência de união apresentaram maior prevalência de fraturas adesivas e maior variabilidade do tipo de falha no mesmo grupo. Como conclusão observou-se que as soluções que combinam silano com outros componentes podem melhorar a adesão entre a cerâmica vítrea e o cimento resinoso sempre que utilizadas em cerâmicas vítreas previamente condicionadas, mas o seu efeito positivo é menor do que o obtido pela solução convencional de silano. Além disso, a interação dessas soluções não convencionais com os cimentos resinosos é material dependente já que nem todos os cimentos avaliados foram afetados
Abstract: The aim of this study was to evaluate the interaction of different silane-containing solutions, with glass ceramic and resin cements by performing a µSBS and failure evaluation. This investigation was separated in two chapters. Chapter 1 verified the influence of four silane-containing solutions (conventional solution, conventional solution followed by a conventional adhesive system, silane-containing universal adhesive system and a silane-containing universal ceramic primer) and previous hydrofluoric acid etching on µSBS of glass ceramic and one conventional resin cement after 24 hours storage. Morphological failure analysis was assessed with a scanning electron microscope. All data was submitted to two-way ANOVA and Tukey test (p<0.05). Results showed that hydrofluoric acid etching was determining to increase µSBS. The only solution that increased significantly µSBS mean value without previous hydrofluoric acid etching was the sole-silane solution. All tested solutions increased µSBS when ceramic was previously etched but with statistical differences between them, being the most effective the sole-silane solution. Cohesive failure in resin cement was associated with higher µSBS values, while ceramic/cement adhesive failure was correlated to lower mean values. In chapter 2 the purpose was to evaluate the interaction of the same silane solutions with five resin cements, three conventional (Rely X Ultimate, Rely X ARC e Variolink II) and two self-adhesive (Bifix e Rely X Unicem 2). Also µSBS test and failure evaluation were performed and results analyzed by ANOVA two-way and Tukey test (p<0.05). Results showed that µSBS was higher when ceramic was treated with the sole-silane solution for all cements. Most of cements showed statistically similar mean values when treated with the universal adhesive and the universal ceramic primer with the exception of BiFix and RelyX ARC. SEM images revealed some incomplete polymerization areas for those cases. Likewise groups that performed better showed more prevalence of cohesive failure in resin cement while groups that presented lower mean values showed more prevalence of adhesive failure and more failure type variability. As conclusion, it was observed that solutions combining silane with other components could improve adhesion between glass ceramic and resin cement whenever employed on previously conditioned ceramics, but their positive effect is lower than the one produced by the sole-silane solution. Furthermore, interaction of those non-conventional silane-solutions with resin cements may be material dependent as not all cements tested were negatively affected
Mestrado
Materiais Dentarios
Mestre em Materiais Dentários
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Bertuoli, Paula Tibola. "Desenvolvimento e caracterização de uma tinta em pó base poliéster contendo montmorilonita funcionalizada com silano." reponame:Repositório Institucional da UCS, 2014. https://repositorio.ucs.br/handle/11338/826.
Full textAbstract:
Dentre os métodos empregados para a proteção à corrosão de materiais metálicos os
revestimentos orgânicos vêm sendo muito utilizados devido a sua facilidade de aplicação e
custos razoáveis. A propriedade de barreira dos revestimentos orgânicos pode ser melhorada
com a incorporação de cargas adequadas, tais como nanocargas que, mesmo em baixas
concentrações, apresentam propriedades de barreira superiores às cargas convencionais. A
montmorilonita (MMT) é a fase inorgânica mais utilizada na obtenção de nanocompósitos
poliméricos. Para melhorar a compatibilidade e dispersão da argila na resina polimérica,
muitos pesquisadores têm realizado o processo de funcionalização da argila utilizando silano.
O presente trabalho tem como objetivo desenvolver e caracterizar uma tinta em pó base
poliéster contendo diferentes teores da argila montmorilonita sódica (MMT-Na+) modificada
com o silano 3-aminopropiltrietoxisilano (γ-APS). A argila modificada com silano (S-MMT)
ou a MMT-Na+ foi incorporada numa formulação padrão de tinta em pó base poliéster nas
proporções de 2, 4 e 8% (m/m). A incorporação da argila na tinta ocorreu no estado fundido
(extrusão). As argilas, a tinta em pó e o revestimento após a cura foram analisados
empregando diferentes técnicas de caracterização, tais como difração de raios X (DRX),
espectroscopia de infravermelho por transformada de Fourier (FTIR), análise
termogravimétrica (TGA), calorimetria exploratória diferencial (DSC), microscopia eletrônica
de varredura (MEV), microscopia óptica (MO). As tintas em pó foram aplicadas sobre painéis
de aço carbono por pulverização eletrostática. O efeito da incorporação de diferentes teores da
argila modificada e não modificada nas propriedades físicas e de proteção à corrosão das
tintas foram avaliadas empregando ensaios de medida de brilho, aderência, flexibilidade,
resistência ao impacto, potencial de circuito aberto (OCP), imersão, impedância eletroquímica
(EIS) e exposição à névoa salina. Através do DRX foi confirmada a modificação e a
intercalação de uma bicamada de moléculas de aminopropil no espaçamento interlamelar da
argila. A S-MMT apresentou uma maior perda de massa do que a MMT-Na+ devido à
presença de silano na sua estrutura. A MMT-Na+ se apresentou na forma de grandes
aglomerados irregulares que se tornaram menores e mais finos após sua modificação com
silano. Nas tintas contendo os diferentes teores de argila (MMT-Na+ ou S-MMT) não foi
constatada a esfoliação da argila, sendo obtido um microcompósito. A partir da caracterização
térmica da tinta em pó constatou-se que os revestimentos contendo a S-MMT apresentaram
menor estabilidade térmica que os demais revestimentos devido à presença do modificador
orgânico. A presença da argila MMT-Na+ ou S-MMT (com exceção de 4% (m/m) da
S-MMT) reduziu a energia liberada no processo de reticulação. Para todos os revestimentos
contendo argila foi constatado o aumento da dureza superficial do revestimento e a redução de
brilho com o aumento do teor de argila, sendo este efeito mais pronunciado com a adição de
8% (m/m) de MMT-Na+. A aderência do revestimento ao substrato e a flexibilidade do
revestimento não foram alteradas pela presença da argila, porém os revestimentos contendo a
S-MMT apresentaram melhores resultados quanto à resistência ao impacto que os
revestimentos contendo a argila MMT-Na+. Tanto nos ensaios eletroquímicos como no de
exposição à névoa salina a modificação da argila com o silano resultou em revestimentos com
melhor desempenho à corrosão que os revestimentos contendo a argila não modificada.
Contudo, a propriedade de proteção à corrosão dos revestimentos contendo argila não foi
superior ao revestimento isento de argila.Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2014-08-25T19:29:58Z No. of bitstreams: 1 Dissertacao Paula Tibola Bertuoli.pdf: 5722201 bytes, checksum: cbb4f785db0e5a8566d49614c04b7264 (MD5)
Made available in DSpace on 2014-08-25T19:29:58Z (GMT). No. of bitstreams: 1 Dissertacao Paula Tibola Bertuoli.pdf: 5722201 bytes, checksum: cbb4f785db0e5a8566d49614c04b7264 (MD5)
Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul, FAPERGS
Among the methods used for corrosion protection of metal materials the organics coatings have been widely used due to their ease of application and reasonable costs. The barrier property of the organic coatings can be improved by incorporation of appropriate fillers such as nanofillers that even in low concentrations show superior barrier properties to conventional fillers. The montmorillonite (MMT) is the inorganic phase more used to prepare polymer nanocomposites. To improve the compatibility and dispersion of the clay in a polymer resin, many researchers have performed the functionalization process of the clay using silane. This study aims to develop and characterize a polyester based powder coating containing different amounts of sodium montmorillonite (MMT-Na+) modified with the silane 3-aminopropyltriethoxysilane (γ-APS). The clay modified with silane (S-MMT) or MMT-Na+ clay were incorporated into a standard commercial formulation of a polyester based powder coating on the ratios of 2, 4 and 8 wt%. The incorporation of clay into the paint was in the molten state (extrusion). The clays, the powder coating and coating after curing were analyzed using different characterization techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and optical microscopy (MO). The powder coatings were applied on carbon steel panels by electrostatic method. The effect of incorporating different amounts of modified and unmodified clay on the physical properties and corrosion protection of the coatings obtained were evaluated using techniques such as gloss measurement, adhesion, flexibility, impact resistance, open circuit potential (OCP), immersion and electrochemical impedance spectroscopy (EIS) in sodium chloride solution and exposure to salt spray. XRD results confirmed the modification and intercalation of a bilayer of aminopropyl molecules in the interlayer spacing of the clay. By thermal analysis the S-MMT clay showed greater loss greater than the MMT-Na+ clay due to the presence of silane in their structure. The MMT-Na+ are presented in the form of large irregular agglomerates that have become smaller and thinner after its modification with silane. In the coatings obtained by incorporating different concentrations of MMT-Na+ or S-MMT it was not detected the exfoliation of clay, characterizing a microcomposite. Through of the thermal characterization of the powder paint it was found that the coatings containing S-MMT clay showed lower thermal stability than other coatings due to the presence of the organic modifier. The presence of MMT-Na+ or S-MMT clay (except 4 wt% of S-MMT clay) reduced the energy released in the process of crosslinking. The surface hardness of the coating was increased and the brightness was decreased with increasing clay content and this effect was most pronounced with the addition of 8 wt% of MMT-Na+. The adhesion of the coating to the substrate and the flexibility of the coating were not changed by the presence of clay, but the clay coatings containing S-MMT showed better results than coatings containing MMT-Na+ regarding the impact resistance. Both electrochemical and exposure to salt spray tests the silane modified clay resulted in coatings with better corrosion performance than those coatings containing the unmodified clay. However, the corrosion protection of the coatings containing montmorillonite was not superior to the coating free of clay.
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Mudry, Guillermo Alejandro. "Revestimentos de silanos obtidos sobre aço carbono e sua utilização como agentes promovedores de adesão em uniões aço-resina epóxi." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2011. http://hdl.handle.net/10183/61013.
Full textAbstract:
A utilização de silanos como agentes promovedores de adesão demonstrou ser uma solução útil para a união entre materiais dissimilares, incrementando a adesão e aumentando inclusive a resistência a corrosão entre os mesmos . A utilização destes agentes como promovedores de adesão, sobre diferentes combinações de materiais, continua sendo estudada atualmente. Este trabalho teve como objetivo avaliar a capacidade de diferentes tipos de silanos como agentes promovedores de adesão. tanto funcionais como não funcionais, na união entre aço SAE 1060 e resina epóxi. Para isto, foram primeiramente obtidos filmes de silano sobre amostras de aço através de diferentes tratamentos. Estes filmes obtidos foram caracterizados por meio de diferentes técnicas. Foram realizados testes de aderência através do método especificado pela norma ASTM D3359 para avaliar a resistência de adesão dos diferentes filmes ao substrato. As amostras testadas foram analisadas através de microscopia eletrônica de varredura (MEV). Também, foram realizadas análises de espectroscopia de energia dispersiva (EDS) sobre as mesmas amostras, permitindo obter outras características dos filmes de silano formados. Os tratamentos que apresentaram melhores resultados na caracterização em MEV/EDS foram escolhidas para a preparação dos corpos de prova de uniões com resina epóxi. Estas uniões foram utilizadas para realizar testes de adesão do tipo arrancamento de modo a avaliar o efeito dos tratamentos com silano na resistência de adesão da união entre o substrato de aço e a resina epóxi. Os resultados dos testes de arrancamento permitem afirmar que existe uma melhoria na resistência de adesão com um dos tratamentos com silano sobre o substrato de aço seguido de revestimento com resina epóxi. A utilização de tratamentos com silanos mostram-se promissoras para esta aplicação.The use of silanes as adhesion enhancer agent proved to be a useful solution for the union of dissimilar materials, increasing the bond strength between them, also increase the corrosion resistance. The use of these agents as adhesion enhancer, with different materials combination, is still being studied today. The aim of this work was to evaluate the ability of different silanes as adhesion agent promoters in joints of SAE 1060 steel and epoxy resin; both functional and not functional silanes. At the beginning and for this purpose were different types of treatments used to obtain silane films on steel samples. Different techniques were used to characterize these films. To evaluate the bond strength adhesion test where performed according to the ASTM D3359 standard. Samples were analyzed with scanning electron microscope (SEM). Energy-dispersive spectroscopy (EDX) analyses were also performed on the same sample allowing to obtain others characteristics of the silane films formed. The treatments that have shown a better performance in the SEM/EDX analyses were selected to make steel and epoxy resins joint samples. These specimens were used to perform pull-out type adhesion test to evaluate the effect of the silanes treatments in the bond strength of steel and epoxy resin joints. The results of de pull-out test indicate that the use of silane improves the bond strength of steel and epoxy resin joints. The use of silane treatments has shown promising results for this application.
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Queiroz, Daniely Ferreira de. "Nanopartículas magnéticas de ferritas recobertas com sílica e funcionalizadas com vinil silano." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/75/75134/tde-04082017-153036/.
Full textAbstract:
Com o desenvolvimento da nanociência e da nanotecnologia, as nanopartículas magnéticas vêm sendo cada vez mais gerado interesse devido as inúmeras possíveis aplicações na área de catálise, diagnóstico, pigmentos, sensores, etc. Atualmente, as nanopartículas com potencialidade de aplicação em biomedicina que pode se destacar os as ferritas magnéticas os quais apresentam comportamento superparamagnético a temperatura ambiente. Além dos ligantes funcionais, as nanopartículas magnéticas são geralmente recobertas com polímeros orgânicos ou inorgânicos, destacando-se a sílica, nessa última classe. O sistemas as nanopartículas magnéticas recobertas com sílica formando um sistema casca-caroço, possibilita que o núcleo magnético se mantenha protegido por uma camada polimérica que pode conter grupos funcionais ativos, formando hidridos orgânicos-inorgânicos que devido a sua propriedade hidrofóbica ou hidrofílica dependendo da natureza do ligante de modificação de superfície. Este trabalho foi desenvolvido com intuito de obter nanopartículas magnéticas de ferrita MFe2O4, com (M= Fe, Co, Ni e Cu) com controle de tamanho, forma, composição química e estrutural, dos quais foram sintetizados pelo método de decomposição térmica utilizando diferente precursores metálicos para adequação das melhores condições de síntese. As ferritas magnéticas foram recobrimento com sílica, modificando da superfície da partícula e possibilitando caráter hidrofílico ao sistema casca-caroço, apresentando uma melhor estabilidade coloidal em dispersão aquosa devido a presença de grupos silanois na superfície, bem como uma recobrimento uniforma com apenas um núcleo magnético sem formação de aglomerados. A funcionalização com o grupo o trietoxivinilsilano, através de reações de condensação via catálise básica ou ácida, formou uma rede polimérica Si-O-Si, sendo que a presença do grupo vinil (-CH=CH2) livre na a superfície do sistema casca-caroço foi evidenciado através da técnica de FTIR. Portanto foi possível a obtenção de um sistema hibrido orgânico-inorgânico com a superfície contendo grupo que podem ser reativos, abrindo a possibilidade da utilização deste material para futuros testes de aplicações como sensor multifuncional.In recent decades the development of nanoscience and nanotechnology, magnetic nanoparticles have been increasingly generated interest due to the numerous possible applications in the field of catalysis, diagnosis, pigments, sensors, etc. Currently, the nanoparticles with potential of application in biomedicine that can stand out the magnetic ferrites which have superparamagnetic behavior at room temperature. In addition to the functional binders, magnetic nanoparticles are generally coated with organic or inorganic polymers, especially silica in the latter class. The magnetic nanoparticle systems covered with silica forming a shell-core system allow the magnetic core to remain protected by a polymeric layer that may contain active functional groups, forming organic-inorganic hydrides that due to its hydrophobic or hydrophilic property depending on the nature of the surface modifying binder. This work was developed to obtain magnetic nanoparticles of MFe2O4 ferrite, with (M = Fe, Co, Ni and Cu) control of size, shape, chemical and structural composition, of which were synthesized by the thermal decomposition method using different precursors to suit the best conditions of synthesis. The magnetic ferrites were coated with silica, modifying the surface of the particle and allowing a hydrophilic character to the shell-core system, presenting a better colloidal stability in aqueous dispersion due to the presence of silane groups on the surface, as well as a uniform coating with only one magnetic core without formation of agglomerates. The functionalization with the triethoxyvinylsilane group, through condensation reactions via basic or acid catalysis, formed a Si-O-Si polymer network, and the presence of the free vinyl group (-CH=CH2) on the shell surface was observed by FTIR technique. Therefore, it was possible to obtain an organic-inorganic hybrid system with the surface containing the reactive group, opening the possibility of using this material for tests of future applications as multifunctional sensor.
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Gau, David. "Synthèse et réactivité des sila-ylures de phosphonium." Toulouse 3, 2011. http://thesesups.ups-tlse.fr/1460/.
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L'objectif principal de cette thèse est l'étude d'espèces siliciées hautement réactives stabilisées par coordination d'un ligand phosphine. Dans un premier chapitre, une étude bibliographique permet de faire le point sur les différents modes de stabilisation des silylènes ainsi que sur leurs propriétés chimiques. Le deuxième chapitre concerne la synthèse d'un sila-ylure de phosphonium dont la structure a été déterminée par diffraction des rayons-X. Cette structure est très différente de celles des analogues carbonés, les réactifs de Wittig. En particulier, le centre silicié est fortement pyramidalisé traduisant une absence de délocalisation de la paire libre du silicium contrairement aux ylures de carbone dont la liaison P-C présente un certain caractère [pi]. Le troisième chapitre traite de la réactivité des sila-ylures de phosphonium. Avec un aldéhyde, ils réagissent de façon similaire aux analogues carbonés et la première réaction de type sila-Wittig (formation d'un silène et d'un oxyde de phosphine) a été mise en évidence. Des études mécanistiques (théoriques et spectroscopiques) montrent que le mécanisme de cette réaction est différent de celui de la réaction de Wittig classique. En particulier, la première étape procède via une cyclo-addition [2+1] concertée, sur le centre silicié, démontrant que les sila-ylures de phosphonium se comportent comme des silylénoïdes nucléophiles. Ainsi, des silirènes hypervalents ont été obtenus par réaction avec des acétyléniques via une cyclo-addition [2+1] impliquant le centre silicié. Ces silirènes à température ambiante se réarrangent de façon diastéréosélective pour conduire à des phosphines P-chirales originales. La synthèse d'un disilyne (Si=Si) stabilisé par des ligands phosphines est décrite dans le quatrième chapitre. Ce dérivé réagit à température ambiante avec quatre équivalents de CO2 conduisant à la formation de CO et d'un disilicate original. Dans le dernier chapitre, l'introduction d'un carbène en [alpha] de la fonction sila-ylure nous a permis d'isoler un dérivé à triple liaison Si=C, un silyne, stabilisé par un ligand phosphine. Il s'agit là du premier exemple d'alcyne hybride organique(C)-inorganique(Si). L'étude de sa réactivité montre que le centre carboné de la triple liaison Si=C se comporte comme un carbène singuletThe main objective of this Thesis is the study of highly reactive silicon species stabilised by the coordination of phosphine ligand. In the first chapter, a bibliographic study provides an update on the different methods of stabilising silylene and their chemicals properties. The second chapter concerns the synthesis of a phosphonium sila-ylide whose the structure has been determined by X-Ray diffraction. This structure is very different to those of analogous carbons, the Wittig reactifs. In particular, the silicon center is strongly pyramidalized representing the absence of delocalisation of the silicon lone pair in contrast to the carbon ylides whose the P-C bond present some [pi]-caracters. The third chapter discusses the reactivity of the phosphonium sila-ylides. With an aldehyde, it reacts in a similar way to carbon analogous and the first sila-Wittig reaction (formation of a silene and phosphine oxyde) has been brought to light. Some mechanistic studies (theoretical and spectroscopic) show that the mechanism of this reaction is different from that of a classical Wittig reaction. In particular, the first step proceeds via a [2+1] concerted cyclo-addition, on the silicon center, demonstrating that the phosphonium sila-ylide behave like nucleophilics silylenoïdes. In this way some hypervalentes silirenes have been obtained by reaction of acetylenics compounds via a [2+1] cyclo-addition involving the silicon centre. These silirenes rearrange themselves at room temperature in a diastereoselective way to lead to original P-chirals phosphines. The synthesis of disilyne (Si=Si), stabilised by phosphine ligands is described in the fourth chapter. This compound reacts at room temperature with four CO2 equivalents, to form CO and an original disilicate. In the last chapter, the introduction of a carbene in an [alpha] position of the sila-ylide function allows us to isolate a triple bond derivative Si=C, a silyne which is stabilized by a phosphine ligand. It's the first example of organic(C)-inorganic(Si) hybride alkyne. The study of this reactivity demonstrates that the carbon center of the triple bond Si=C behaves like a singular carbene
Books on the topic "Silani"
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Pontieri, Pietro. Tra le storie e la gente dei paesi silani. Cosenza: Editoriale Progetto 2000, 1997.
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Institut Teknologi Bandung. Kelompok Keahlian Perancangan Arsitektur. Arus silang. Bandung, Indonesia: Sekolah Arsitektur, Perencanaan, dan Pengembangan Kebijakan, Kelompok Keahlian Perancangan Arsitektur, Institut Teknologi Bandung, 2010.
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Kuncoro, Sanie B. Silang hati. Ciganjur, Jagakarsa, Jakarta: GagasMedia, 2012.
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Vlachakē, Marinella. Silans silvouple. Athēna: Kedros, 2006.
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Basile, Saverio. Leggende silane. San Giovanni in Fiore: Basile, 1987.
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Dušan Silni. Beograd: Knjiga-komerc, 2002.
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V, Dugas, ed. Use of organosilanes in biosensors. Hauppauge, N.Y: Nova Science Publishers, 2010.
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Plueddemann, Edwin P. Silane Coupling Agents. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4899-2070-6.
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Kusnandar, Dadang. Cirebon, silang peradaban. Yogyakarta: Gapura Publishing.com, 2012.
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Silane coupling agents. 2nd ed. New York: Plenum Press, 1991.
Find full textBook chapters on the topic "Silani"
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Baruah, J. B. "Catalysts for Silane and Silanol Activation." In ACS Symposium Series, 69–80. Washington, DC: American Chemical Society, 2007. http://dx.doi.org/10.1021/bk-2007-0964.ch006.
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Gooch, Jan W. "Silane." In Encyclopedic Dictionary of Polymers, 663. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_10630.
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Irvine, William M. "Silane." In Encyclopedia of Astrobiology, 2263–64. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-662-44185-5_1818.
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Irvine, William M. "Silane." In Encyclopedia of Astrobiology, 1510. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-11274-4_1818.
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Irvine, William M. "Silane." In Encyclopedia of Astrobiology, 1. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-27833-4_1818-4.
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Irvine, William M. "Silane (SiH4)." In Encyclopedia of Astrobiology, 1. Berlin, Heidelberg: Springer Berlin Heidelberg, 2021. http://dx.doi.org/10.1007/978-3-642-27833-4_1818-5.
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Zajac, Peter. "Silan, Janko." In Kindlers Literatur Lexikon (KLL), 1. Stuttgart: J.B. Metzler, 2020. http://dx.doi.org/10.1007/978-3-476-05728-0_21065-1.
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Weissenbach, Kerstin, and Helmut Mack. "Silane Coupling Agents." In Functional Fillers for Plastics, 57–83. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527605096.ch4.
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Borup, Björn, and Kerstin Weissenbach. "Silane Coupling Agents." In Functional Fillers for Plastics, 61–90. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2010. http://dx.doi.org/10.1002/9783527629848.ch4.
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Gooch, Jan W. "Silane Coupling Agent." In Encyclopedic Dictionary of Polymers, 663–64. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_10631.
Full textConference papers on the topic "Silani"
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Bouyer, E., M. Müller, G. Schiller, and R. Henne. "Conversion of Silanes Into SiC by RF Plasma Technology." In ITSC 1999, edited by E. Lugscheider and P. A. Kammer. Verlag für Schweißen und verwandte Verfahren DVS-Verlag GmbH, 1999. http://dx.doi.org/10.31399/asm.cp.itsc1999p0853.
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Abstract This paper reports on the synthesis of SiC material through the decomposition of silanes in a thermal high frequency (HF) plasma. The process is based on thermal plasma technology for chemical deposition from the gas phase and on suspension plasma spray technology, in which a liquid or suspension is injected axially and atomized in the plasma flame. The liquid silane then decomposes, and forms SiC with some gaseous by-products such as HCl. Various plasma parameters were varied, for example the plasma power level, the plasma gas composition, the chamber pressure, and the silane composition. The paper also presents first investigations into the elementary and phase composition as well as the morphology of the powders and coatings. Paper includes a German-language abstract.
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Mullin, C. S., P. Guyot-Sionnest, M. Feller, W. Chen, and Y. R. Shen. "SHG investigation of liquid crystal-silane interfaces." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1988. http://dx.doi.org/10.1364/oam.1988.wb4.
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Using optical second harmonic generation, we have studied the interaction between 4′-n-octyl-4-cyanobiphenyl (8CB) liquid crystal molecular monolayers and glass substrates treated with three types of silane coupling agent: MAP, DMOAP, and OTS. On adsorption from the gaseous phase at atmospheric pressure, we measure the coverage, orientation, and binding energy of monolayers on these substrates and find that, although the bulk alignment differs from different silanes, the alignment of the monolayer is unaffected. We also find a polar layer of liquid crystal at the surface of MAP and DMOAP, unlike the dimerized layers that are found in the bulk liquid crystal. The number of binding sites on these silanes is approximately equal and less than the number of sites on clean glass. Their binding energies are also slightly below that on glass. On OTS, no polar layer formed, although a dimerized bilayer was present.
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Baruwa, Akinsanya Damilare, Esther Titilayo Akinlabi, O. P. Oladijo, and Frederick Mwema. "Structural and Mechanical Analysis of Silane Compounds Coatings on AISI 304." In ASME 2019 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/imece2019-10721.
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Abstract The structures and mechanical strength existing in three different hydrophobic silane compounds, Henicosyl-1,1,2,2-tetrahydrododecyltrichlorosilane (FDDTS), Tridecafloro-1,1,2,2-tetrahydrooctyltrichlorosilane (FOTS) and [Tris(trimethylsiloxy)silyethyl]dimethylchlorosilane (Alkyl) under same deposition conditions were studied and presented in this paper. The effect of the chemical composition on the mechanical strength and the structural evolutions as related to chlorosilane was inquired. The structures were investigated by using field emission scanning electron microscope (FESEM), atomic force microscope (AFM) and surface profiler while the nature of the mechanical strength was determined from nanoindentation and nano scratch. From the data obtained, the FDDTS showed to be denser in structures than both Alkyl and FOTS. The root-mean-square (RMS) roughness exhibited by FDDTS was larger when compared to the other two silanes. The mechanical ability shows that the FDDTS has the largest maximum penetration load as well as highest scratch resistance. Overall, the FDDTS would perform excellently in the applications where combine hard and wear resistance organic coating is required.
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Sohawon, Haris, and Hans Beushausen. "The effect of hydrophobic impregnation on chloride ingress into cracked concrete." In IABSE Congress, New York, New York 2019: The Evolving Metropolis. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2019. http://dx.doi.org/10.2749/newyork.2019.1963.
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<p>Premature concrete degradation due to rebar corrosion has many financial and social implications on a large scale. Direct costs relate to the repair and rehabilitation of existing structures to maintain serviceability while indirect costs include loss in productivity and reduced economic growth. Hydrophobic (silane) impregnation represents a cost-effective way to increase the durability of concrete structures in cases where insufficient design cover quality and depth have been achieved. The water repellent product lines the internal capillary pore structure and provides a water-repellent concrete surface. Thus, the risk of reinforcement corrosion initiation and subsequent deterioration can be reduced as the ingress of water-dissolved aggressive species (chlorides) is minimised or prevented. The purpose of this study was to investigate and quantify the influence of silane impregnation as a remedial measure for poor quality or insufficient cover depth in newly constructed structures and ultimately predict the service life extension possible for specific cover depths. The effectiveness of silane impregnation in cracked concrete was also studied. The results indicate that silane impregnation reduces capillary absorption and conductivity of chloride ions for all the mixes. Chloride ingress in the treated concrete mixes was suppressed and lower chloride surface concentration (C<sub>s</sub> and apparent chloride diffusion coefficient (D<sub>a</sub>) were recorded. A slight decrease in carbonation depth was observed in the w/b 0.60 concrete mixes. The results also suggest that silane impregnation reduces chloride ingress in cracked concrete (up to a crack width of 0.6 mm). A lower rate of chloride ingress was predicted in the silane treated concrete and consequently to achieve the same service life, smaller cover depths are required. The overall results indicate that the service life of concrete with inadequate cover depth and quality, regardless of the binder type, can be effectively extended using hydrophobic (silane) impregnation, assuming proper surface preparation and application methods.</p>
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Feng, Ziwei, Xueyan Zhang, Jianhui Su, Yifan Liu, Hongyun Zhao, Bo Chen, Xiaoguo Song, and Caiwang Tan. "Influence of Silane Treatment on the Joint Properties During Laser Joining of Aluminum Alloy to CFRTP." In ASME 2022 17th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/msec2022-85298.
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Abstract Achieving strong joining of aluminum alloy to carbon fiber thermoplastic composites (CFRTP) using laser heating was an essential method to reduce the weight of structure and save energy. In current study, a silane coupling agent was adopted on the aluminum alloy surface to improve the bonding strength of the laser joining of aluminum alloy to CFRTP. Substrate characteristics of the aluminum alloy after treatment including surface morphology, surface roughness and wettability as well as chemical composition were then studied. For comparison, identical experiments were also performed for the polished and sanded aluminum alloy. Compared to the aluminum alloy polished, the surface roughness of aluminum alloy sanded and silane treated was increased, whereas the wettability was both decreased. The rougher surface led to a worse wettability of aluminum alloy surface for these two specimens. In addition, the detected organo-functional group for the latter was also responsible for the increase of water contact angle on the aluminum alloy surface. Compared to the polished specimens, the tensile shear force of joints for sanded and silane-treated substrates averaged 1106.9N and 2959.4N respectively, which represents a respective increase of 1.2 times and 3.3 times than the polished state. Correspondingly, the tensile shear strength of joints was 6.3MPa and 16.8MPa, which was increased by 1.1 times and 2.9 times, respectively. The improved mechanical interlocking induced by increasing the surface roughness in both sanded and silane treated cases was considered to strengthen the bonding strength at the interface. Moreover, for the joints fabricated by aluminum alloy silane treated and CFRTP, the remarkable enhancement of joint strength was also related to the formation of silane coupling film on the aluminum alloy surface. The tensile shear properties of joints were also found to have a positive influence in increasing the adhesion amount of CFRTP on the fractured surface of aluminum alloy. Finally, the silane treatment was expected to play a significant role in joining aluminum alloy to CFRTP.
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NORTHAM, G., A. MCLAIN, G. PELLETT, and G. DISKIN. "Effect of silane concentration on the supersonic combustion of a silane/methane mixture." In 22nd Joint Propulsion Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1986. http://dx.doi.org/10.2514/6.1986-1396.
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Goh, C. S., S. C. Tan, S. L. Ngoh, and J. Wei. "The Influence of Nanofillers and Additives on the Adhesion Strength of Aluminum." In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-38547.
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In this study, adhesives with Al2O3 nanofillers or silane additives incorporated have been developed. Functionalization of the Al2O3 nanofillers has been carried out to improve the bonding of the fillers to both the adhesive and Al substrate. The silane coupling agents on the nanofillers can react with the Al2O3, Al substrate and adhesive through their functional end groups and form strong covalent and hydrogen bonds which can improve the lap shear strength of the adhesive substantially. An improvement in lap shear strength has also been achieved when glycidoxypropyltrimethoxysilane is added directly into Epon 160 adhesive. There is also an obvious change in fracture mode from adhesive to cohesive due to the effect of silane addition which facilitates bond formation between the adhesive and Al substrate.
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Zhao, Jiheng, Debra A. Sheadel, and Wei Xue. "Surface Treatment of Polymers for the Fabrication of All-Polymer Microfluidic Devices." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-86136.
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Polymer microfluidics has received considerable attention due to their low cost, remarkable biocompatibility, and high flexibility when compared to glass and silicon devices. However, the fabrication process of all-polymer devices can be complicated. In particular, different types of polymers possess different properties in terms of surface chemistry and hydrophilicity, making device assembly a challenging task. In this paper, we demonstrate the fabrication of an all-polymer device through the investigation of the essential surface treatment methods. A hybrid SU-8-SU-8-polydimethylsiloxane (PDMS) sandwiched structure is used in this research. Both untreated SU-8 and PDMS are hydrophobic and they have different surface chemistry properties, so surface modifications are necessary. Three critical surface treatment steps are used in our process. The first step is to treat the first SU-8 layer with low-power (10 W) oxygen plasma, making its surface hydrophilic. This step enables the uniform coating of the second SU-8 layer. The next surface treatment is on the second SU-8 layer. Both oxygen plasma (40 W) etching and diluted 3-aminopropyltriethoxysilane (APTES, a silane solution) coating are needed. APTES introduces amine (Si-NH2) groups on the surface. The last treatment step is to introduce silanol (Si-OH) groups on PDMS using oxygen plasma. These surface treatment steps are critical in the fabrication process and can determine the quality of the final device.
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Daniels, John L., and Mimi S. Hourani. "Soil Improvement with Organo-Silane." In U.S.-China Workshop on Ground Improvement Technologies 2009. Reston, VA: American Society of Civil Engineers, 2009. http://dx.doi.org/10.1061/41025(338)23.
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Bardhan, Anirudh, Fahad Khan, Himanshu Kesarwani, Sushipra Vats, Shivanjali Sharma, and Shailesh Kumar. "Performance Evaluation of Novel Silane Coated Nanoparticles as an Additive for High-Performance Drilling Fluid Applications." In International Petroleum Technology Conference. IPTC, 2023. http://dx.doi.org/10.2523/iptc-22878-ms.
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Abstract Improving water-based drilling fluid properties to mitigate instability issues at elevated temperatures is the need of the hour. In this study, industrially prepared silica nanoparticles (NPs) coated with AEAPTS ([3-(2-Aminoethylamino) propyl] trimethoxy silane) was used as an additive to enhance the rheology and control filtration of the water-based mud. Silica nanoparticles were coated separately in a two-step process, which involved the addition of a hydroxyl group first and then coating with AEAPTS. To check its applicability in water-based drilling fluids rheological and filtration tests were done with varying NP concentrations of 0.2, 0.3, and 0.4 w/v %. The rheology values of the mud samples were recorded both before and after the thermal aging of mud in the roller oven at 105°C for 16 hours. The filtration test was carried out according to API standards with 100 psi differential pressure for 30 minutes. The silane coating over the silica NPs was confirmed with the shifting in the peaks of the FTIR (Fourier Transform Infrared) spectra of the sample. Both the plastic viscosity (PV) and the apparent viscosity (AV) of the drilling fluid were found to be increasing with silane-coated silica nanoparticles’ inclusion when tested at 30°C and 60°C. The degradation in the rheology of the base mud without nanoparticles after thermal aging was found to be around 60 % which was reduced to around 20 % with the addition of the coated silica nanoparticle. Also, a remarkable reduction in the filtrate volume, when compared with base mud, was achieved with the addition of the silane coated NP in the mud. The results show that the novel AEAPT silane-coated silica NPs can be used as a rheology modifier and filtration control additive in water-based drilling fluid for high-temperature drilling applications.
Reports on the topic "Silani"
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Thoreson, Dale. Use of “Corn Picker for Silage” to Evaluate Corn Silage Hybrids. Ames (Iowa): Iowa State University, January 2010. http://dx.doi.org/10.31274/ans_air-180814-90.
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Mur, Remco. LISTENING TO THE SILENT PATIENT. Wallingford: CABI, 2015. http://dx.doi.org/10.1079/cabiplant-37-55.
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Dahlke, Garland R. Corn Silage to Beef Calculator. Ames (Iowa): Iowa State University, January 2017. http://dx.doi.org/10.31274/ans_air-180814-454.
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Maresca, Paul, Jeffrey M. Cox, James Rosati, and III. Silent Inspector System, Technical Manual. Fort Belvoir, VA: Defense Technical Information Center, February 1996. http://dx.doi.org/10.21236/ada304931.
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Bentley, Jennifer A. Use of “Corn Picker for Silage” to Evaluate Corn Silage Hybrids 2010 Trials Update. Ames (Iowa): Iowa State University, January 2011. http://dx.doi.org/10.31274/ans_air-180814-673.
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Thoreson, Dale R. Use of “Corn Picker for Silage” to Evaluate Corn Silage Hybrids 2009 Trials Update. Ames (Iowa): Iowa State University, January 2011. http://dx.doi.org/10.31274/ans_air-180814-737.
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Mazza, James J., Jason B. Avram, and Ronald J. Kuhbander. Grit-Blast/Silane (GBS) Aluminum Surface Preparation for Structural Adhesive Bonding. Fort Belvoir, VA: Defense Technical Information Center, April 2003. http://dx.doi.org/10.21236/ada415239.
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Evan Fricke, Evan Fricke. The Fate of a Silent Forest. Experiment, April 2012. http://dx.doi.org/10.18258/0007.
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Mignani, Gerard, and Dietmar Seyferth. Some Useful Bis(trimethylsilylamino)silanes (Preprint). Fort Belvoir, VA: Defense Technical Information Center, November 1992. http://dx.doi.org/10.21236/ada258271.
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Euken, Russ. Corn Silage and Earlage Nutrient Analysis. Ames (Iowa): Iowa State University, January 2018. http://dx.doi.org/10.31274/ans_air-180814-554.
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