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Showing 1 to 20 of 21 for “"Silanol groups"”.
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Studies of the formation of homogeneous mixed silicon-titanium/zirconium oxides by the sol-gel route
… (from 0.56-0.001cm3g-1') and relative number of silanol groups on the surface of the sample above 700°C. Average pore diameters remain constant at temperatures below 900°C (ca 54-21Å for monoliths), although the micropore volume does decrease (0.04-0.0cm3g-1) suggesting that smaller pores are …
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Temperature Programmed Desorption and Infrared Spectroscopic Studies of Interfacial Hydrogen Bonds for Small Molecules Adsorbed on Silica and Within Metal Organic Frameworks
… of desorption. 2-CEES has two polar functional groups, the chloro and thioether moieties, available to accept hydrogen bonds from free surface silanol groups. Diethyl sulfide and chlorobutane were investigated to independently assess the roles of the chloro and thioester moieties in the overall …
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Durability and Adhesion of a Model Epoxy Adhesive Bonded to Modified Silicon Substrates
… longer oxygen plasma pretreatment times, more silanol groups may be available to interact with the hydrolyzed silanol groups on silane, resulting in a stronger SCA-Si attachment. Three different tests were employed to determine adhesion and durability of the model epoxy/SCA/SiO2/Si bonded …
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Probing the Hydrogen Bonding Interaction at the Gas-Surface Interface using Dispersion Corrected Density Functional Theory
… surface was approximated using a gas-phase silanol molecule and clusters containing a single hydroxyl moiety. Recent temperature programmed desorption experiments performed in UHV concluded that sulfur mustard and its less toxic mimics undergo molecular adsorption to amorphous silica. …
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Studies of adsorption and stabilization of silica suspensions using well-defined polymeric dispersants
… by hydrogen bonding between the carbonyl groups on the polymer and surface silanol groups. The difference in adsorption energies in water and ethanol reflect specific solvent effects that may be related to the formation of hydrogen bond bridges between PEOX and silanol groups in water. …
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METHOD DEVELOPMENT FOR THE ANALYSIS OF PROTEINS AND SMALL
… wall, arising from the ionization of surface silanol groups. Presented here is a method for quantitation of protein-dye complexes using a self assembled, surfactant-coated capillary and on-column protein labeling with a non-covalent squarylium dye, Red-1c. Second, seasonal sugar levels are …
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Study of the thermal behaviours of intumescent silicate materials
… the evaporation of water of condensation from silanol groups iv) the decomposition of samples and i) structural rearrangement. Cone calorimetry studies revealed that samples with low polyol (P) and high SiO2:Na2O weight ratio (WR) exhibited very low heat release rates (HRR) and vice versa. It …
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The Reactivity of Chemical Warfare Agent Simulants on Carbamate Functionalized Monolayers and Ordered Silsesquioxane Films
… carbamate linkages. In addition, novel trisilanolphenyl-polyhedral oligomeric silsesquioxane (POSS) molecules were used to create Langmuir-Blodgett films containing reactive silanol groups that have potential use as sensors and coatings. The uptake and reactivity of organophosphonates and …
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Nitrophenyl boronic acids as derivatizing agents in chromatography
… limited by the column activity due to residual silanol groups, this tends to decompose all but the most stable boronates. However, excellent results were obtained in the case of 2,4-pentandiol boronates, reaching detection limits in the picomole level with a variable wavelength ultraviolet …
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An exploration of the mechanism of hydrophilic interaction chromatography (HILIC) and the application of HILIC in metabolomic profiling
… to shield the acid from repulsion by charged silanol groups on the silica gel surface. The neutral test probes were increasingly retained with increasing ionic strength of the mobile phase suggesting that the thickness of the water layer on the surface of the silica gel increased with the …
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Effects of long-chain surfactants, short-chain alcohols and hydrolyzable cations on the Hydrophobic and Hydration Forces
… of the water molecules H-bonded to the silanol group by methanol, which in turn destroys the water structure in the vicinity of the silica surface. Methanol can displace water from the silanol group because it is more basic than the water. Ethanol, on the other hand, cannot cause the …
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Silica Dispersion for Applications in Rubber Processing
… molecules. The CA chemically binds to surface silanol groups so that interparticle and particle-polymer interactions are modified in a manner that improves the silica dispersion quality as well as the processability of silica-reinforced rubber composites. However, the control of CA-silica …
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Preparation, type and stability of emulsions stabilised by solid particles
… phase. Increasing the pH causes dissociation of silanol groups, which increases the affinity of the particles for the aqueous phase. The type and stability of emulsions and the contact angle of an aqueous drop under toluene on hydrophobically modified glass slides were measured as a function of …
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Studies on the Degradation of Desiccants in Temperature Swing Adsorption Processes and the Adsorptive Separation of Sulfur Compounds from Industrial Fluids
… H2S increased when the concentration of surface silanol groups increased. The adsorption of multi component CH4/CO2/H2S, N2/CO2/SO2, and N2/CO2/SO2/H2O mixtures on activated carbons derived from petroleum coke were collected. It was concluded that the selectivity of H2S/CH4 increased when the …
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Interfacial Interactions in Polyaniline Containing Hybrids
… It has focused on the interaction of two groups of substrates with PANI: inorganic fillers and biopolymers. The first group includes model substrates, such as silica and alumina, and also zeolites and clays, where the silanol groups on their surfaces were considered as the target for …
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Structure-property behavior of hybrid materials incorporating oligomeric species with inorganic silicates by a sol-gel process
… one of three types of oligomers, which included silanol terminated polydimethylsiloxane (PDMS), triethoxysilane endcapped polytetramethyleneoxide (PTMO), and PTMO with multiple triethoxysilane functional groups. The general reaction scheme was to first generate silanols from both components …
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Χημική δομή και μεσοφασικές δράσεις τεσσάρων σιλανιούχων σκευασμάτων επιδιόρθωσης κεραμικών όψεων
… instrument. II) assessement of the activity of silanol -OH groups in the prehydrolyzed materials by Ή-ΡΓ NMR and the D2 0 technique. III) scanning electron microscopy and electron probe microanalysis of the alloy-composite and porcelain-composite repaired interfaces, with intermediate silane …
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Characterisation of silica in Equisetum hyemale and its transformation into biomorphous ceramics
… to the epidermis cell walls. It is lacking silanol groups and is intimately associated with polysaccharides (cellulose, hemicellulose, pectin) and inorganic compounds. Silica deposited in E.hyemale is found to be mostly amorphous with almost negligible amounts of crystalline silica in the …
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Design, Synthesis and Characterization of Porous Silica Nanoparticles and Application in Intracellular Drug Delivery
… of infected mice. Furthermore, the presence of silanol groups provides the ability to functionalize the silica xerogel system with organic groups, poly (ethylene glycol) (PEG), to further increase the hydrophilicity of the silica xerogel matrix and to modify the drug release properties. Increase …
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The Influence of Amorphous, Sub-Micrometer Silica Particles in Cement Pastes and Mortars with Very Low Water-to-Cement Ratios (Ultra-High Performance Concrete)
… of the specific surface area, surface silanol group density, total content of silanol groups and solubility in alkaline suspension. Results indicate that Stoeber particles are by far the most reactive, followed by pyrogenic silica and the less reactive silica fume. Silica reactions are …
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