Liquid impregnation composites

In both situations the interaction of the medium inside the pore with the pore wall (1) is increased (2) or changed which affect the transport and separation properties (surface diffusion, multilayer adsorption) and/or help overcome equilibrium constraints in membrane reactors. Membrane modifications can be performed by depositing material in the internal pore structure from liquids (impregnation, adsorption) or gases. Several modification possibilities are schematically shown in Figure 2.3. Some results obtained by Burggraaf, Keizer and coworkers are summarized in Table 2.7. Composite structures on a scale of 1-5 nm were obtained. 

Carbon-Fiber-Reinforced Carbon Composites Fabricated by Liquid Impregnation... 

Carbon/carbon composites fabricated by multiple cycles of liquid impregnation and recarbonization are a typical example of modern petroleum derived carbons. In the 1975 ACS Symposium on Petroleum Derived Carbons (JL), papers were presented on carbon/carbon composite materials formed by pyrolytic infiltration processes (2 ) or by liquid impregnation with petroleum pitch (3,4), on fabrication processes for high-modulus carbon fibers based on polyacrylonitrile (PAN) or pitch precursors ( 5 ), and on the use of carbon materials for thermostructural (6 ) as well as biomedical applications (1 ) ... 

Multidimensional BN fiber infiltrated (matrix) composites are analogous to carbon-carbon composites and overcome the brittleness and low to moderate thermal shock resistance of hot-pressed BN. With the availability of BN fibers (see 17.3.5.4), a weave of three or more dimensions is possible. Chemical vapor deposition may produce a turbostatic BN matrix that is sensitive to H2O, while liquid impregnation requires multiple reimpregnation cycles h One scheme is to impregnate a BN woven fiber preform with H3BO3, dry, sinter in NH3, and hot-press. 

The carriers were impregnated to different compositions in terms of vanadium content, K/V ratio, Na/V ratio, Cs/V ratio and sulphur content, cf. Fig. 8. The exact sulphur content is less important since the melt, according to reaction (2), takes up an equilibrium amount of SO3 corresponding to a sulphur to alkali metal molar ratio of about 1 during operation in synthesis gas. The impregnation was carried out by submerging the pellets for a period of time in a surplus of aqueous impregnation liquid prepared from sulphuric acid and water-... 

The factors 4 and 4 accormt for the heterogeneity of the interface. The interfacial flux conditions. Equations (6.56) and (6.57), can be straightforwardly applied at plain interfaces of the PEM with adjacent homogeneous phases of water (either vapor or liquid). However, in PEFCs with ionomer-impregnated catalyst layers, the ionomer interfaces with vapor and liquid water are randomly dispersed inside the porous composite media. This leads to a highly distributed heterogeneous interface. An attempt to incorporate vaporization exchange into models of catalyst layer operation has been made and will be described in Section 6.9.4. 

Note 2 Composite laminates generally consist of one or more layers of a substrate, often fibrous, impregnated with a curable polymer, curable polymers, or liquid reactants. 

C. P. Spaeth, 29, 5660 (1935) Ignition composition for the top charge in blasting caps, comprised of NC impregnated with a liquid explosive nitric ester, such as NG and KC103 USP 2007223 (1935)... 

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