Structural and surface properties

Reinforcing fibers can be modified by physical and chemical methods. Physical methods, such as stretching [22], calandering [23,24], thermotreatment [25], and the production of hybrid yarns [26,27] do not change the chemical composition of the fibers. Physical treatments change structural and surface properties of the fiber and thereby influence the mechanical bondings in the matrix. 

For the studied catechol methylation reaction the catalyst structure and surface properties can explain the catalytic behaviour As mentioned above, the reaction at 260-350°C has to be performed over the acid catalysts. Porchet et al. [2] have shown, by FTIR experiments, the strong adsorption of catechol on Lewis acid/basic sites of the Y-AI2O3 surface. These sites control the reaction mechanism. 

R Ratnasamy, A. I. Leonard, L. Rodrique, and I. I. Fripiat, Structure and surface properties of supported platinum catalysts, J. Catal 29, 374-384 (1973). 

Sphalerite, which is also known as Blende, is an important mineral of zinc. Most natural sphalerite contains iron more or less in lattice with the amount depending on the chemical environment and temperature (Lusk et al., 1993). High iron sphalerite is called marmatite. The studies of the electronic structure and surface properties of ZnS and transition metal doped ZnS are of interest from both a fundamental and practical perspective. As discussed in Chapter 6, sphalerite has... 

In addition to mesostructured metal oxide molecular sieves prepared through supramolecular assembly pathways, clays, carbon molecular sieves, porous polymers, sol-gel and imprinted materials, as well as self-assembled organic and other zeolite-like materials, have captured the attention of materials researchers around the globe. Clays, zeolites and sol-gel materials are still very popular because of their extensive and expanding applications in catalysis and separation science. Novel carbons and polymers of ordered porous structures have been synthesized. There are almost unlimited opportunities in the synthesis of new organic materials of desired structural and surface properties via self-assembly or imprinting procedures. 

The structurally programmable micro fluidic system consists of passive valves and flow conduits, which provide different pressure drops. These pressure drops depend on the structure and surface properties of the fluidic paths. The pressure drops can be controlled by tailoring the length of the flow paths and the relative restriction ratio of the passive valves [71]. 

Aramendia, M. A., Borau, V., Jimenez, C., Marinas, J. M., Ruiz, J. R. and Urbano, F. J. Influence of the preparation method on the structural and surface properties of various magnesium oxides and their catalytic activity in the Meerwein-Ponndorf-Verley reaction, Appl. Catal., A, 2003, 244, 207-215. 

Kornilovich, Boris, Structure and Surface Properties of Mechanochemically Activated Silicates and Carbonates. Kiev Naukova Dumka, 1994. 

The synthesis of phenolic-formaldehyde and melamine-formaldehyde resins in the presence of fumed silica allows obtaining porous organic materials with a differentiated porous structure and surface properties. The pore characteristics of the studied resins in dry state were determined from nitrogen adsorption isotherms. The differences in surface character of the synthesized polymers were estimated satisfactorily by XPS spectra showing the presence of various functional groups. The adsorption/desorption mechanism of water and benzene on the investigated porous polymers was different due to differentiated hydrophobicity of the bulk material. 

S. J. Park and Y. S. Jang, Pore structure and surface properties of chemically modified activated carbons for adsorption mechanism and rate of Cr(VI), J. Colloid Interface Sc/. 249 (2002) 458-463. 

Effect of Chemical Structure and Surface Properties of Synthetic Polymers on the Coagulation of Blood. II. Protein and Platelet Interaction with Polymer Surfaces, Trans. Amer. Soc. Artif. Int. Organs (1968) 14, 250. 

To control the surface properties of silica (reduced filler-filler interactions, advanced filler-polymer interactions, minimized moisture uptake of the silica), it is necessary to modify the silica surface with silanes. Thickening behavior of silica, for example, is related to structure and surface properties of the silica. 

H. Gerischer, The role of semiconductor structure and surface properties in photoelectrochemical processes, J. Electroanal. Chem. 15B, 553, 1983. 

Hydrogels that coat metal and semiconductor nanoparticles are of considerable interest because of their unique size-dependent physicochemical properties. Precise control of the structure and surface properties... 

Jean, K., Renan, M., Famelart, M.H., and Guyomarc h, F. (2006). Structure and surface properties of the serum heat-induced protein aggregates isolated from heated skim milk. Int. Dairy J. 16, 303-315. 

In principle it would seem reasonable that the bulk structure and surface properties of a solid would influence the catalytic performance. Verification of this view and an assessment of its importance may be more significant than first appears since it incorporates an implication that catalytic preparation should be designed to achieve the bulk structure and surface properties that give the optimized catalytic performance. Materials which have been shown to catalyze the conversion of propylene to acrolein have included metal oxides, mixed oxides, and more lately the multicomponent catalysts. A consideration of all these solids would require the assessment of numerous data and speculation. However, the mixed oxide catalysts have been associated with many of the more recent investigations of the course of catalytic oxidation, and these catalysts therefore seem to be worthy of detailed consideration. 

Yu, G., Saha, U. K., Kozak, L. M., and P. M. Huang (2007). Combined effects of tannate and aging on structural and surface properties of aluminum precipitates. Clays Clay Miner. 55, 369-379. 

Commercial availability of a spectrum of adsorbents like activated carbons, zeolites, aluminas, silica gels, and polymeric materials having a variety of pore structures and surface properties and exhibiting a variety of core adsorptive properties like equilibria, kinetics, and heats for the gas separation or purification application. 

Manganese oxides, which have different structural and surface properties, vary in their ability to promote the precipitation and crystallization of Fe oxides and oxyhydroxides (Krishnamurti and Huang, 1988). The standard electrode potential (E°) of the redox pairs Fe -MnO2 and Fe -Mn3O4 can be described by the following equations (Bricker, 1965)... 

Among metalloids, the toxic As(III) has been proven to be oxidized to the less toxic As(V) by Mn oxides. The ability of Mn oxides to oxidize As(III) varies with their structural and surface properties. The extent of masking of the electron-accepting sites on the Mn oxides for oxidation of As(III) to As(V) substantially varies with the kinds and levels of coatings. Reactive Mn oxides may be added to some environments, that have been contaminated with As(III), to alleviate the toxicity of As(ni) through converting As(III) to the less toxic and mobile As(V). 

The behavior of colloidal silica is based on its morphology and structure and on the chemistry of its surface. To fully characterize colloidal silicas one must pleasure not only the particle size, particle size distribution, surface area, and degree of aggregation, but also the structural and surface properties. 

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