Interlayer migration

The viscosity drop becomes more pronounced in the whole range of (f> (0% < (f) < 100%) when A (l - A) increases, indicating that the value of parameter K considerably affects the flow behavior of the blend (Fig. 3). Note that (1 - A) is related to the fibrillation and migration of TLCP-rich interlayer. 

The interconnect material is in contact with both electrodes at elevated temperatures, so chemical compatibility with other fuel cell components is important. Although, direct reaction of lanthanum chromite based materials with other components is typically not a major problem [2], reaction between calcium-doped lanthanum chromite and YSZ has been observed [20-24], but can be minimized by application of an interlayer to prevent calcium migration [25], Strontium doping, rather than calcium doping, tends to improve the resistance to reaction [26], but reaction can occur with strontium doping, especially if SrCr04 forms on the interconnect [27],... 

In a similar study (Comans et al., 1990), the reversibility of Cs+ sorption on illite was studied by examining the hysteresis between adsorption and desorption isotherms and the isotopic exchangeability of sorbed Cs+. Apparent reversibility was found to be influenced by slow sorption kinetics and by the nature of the competing cation. Cs+ migrates slowly to energetically favorable interlayer sites from which it is not easily released. 

Theoretical calculations [43] based on first principles molecular dynamics discussed in Sect. 3.2.6 have suggested that Mg Al LDHs are most stable for n = 3 (i.e. x = 0.25) and indeed many minerals, including hydrotalcite itself, have this stoichiometry [4]. It has been reported that the synthesis of LDHs (with benzoate or terephthalate anions in the interlayers) from solutions containing Mg/Al = 2, leads to LDHs having the same composition when the synthesis is carried out at moderate temperatures but LDHs with Mg/Al = 3 (plus AlOOH) when the reaction is carried out under hydrothermal conditions [44]. It was proposed that the latter ratio represents the thermodynamically most favorable product. A similar observation has been reported [45] for solutions with Ni VPe = 2, where hydrothermal preparation led to segregation of an LDH with Ni VPe = 3 and Ni Fe 204. An attempt to synthesize a Co sAl LDH resulted in partial oxidation of the Co and formation of a Co o.yCo o.s LDH with complete migration of Al " from the layers to generate interlayer aluminum oxy-species [46]. 

Hydrothermal studies by Roy and Romo (1957) indicate that macroscopic vermiculite cannot form above 200-300°C. At these temperatures some of the octahedral ions migrate into the interlayer positions and a chlorite-like phase is formed. 

When electrons are excited from the 0(2p) band to the Fe(3d) band, what kind of orbital pathways may allow holes in the 0(2p) band to migrate to the surface or interlayer region and facilitate electron transfer processes ... 

Marosi, G., Marton, A., Szep, A., Csontos, I., Keszei, S.,Zimonyi, E.,Toth, A., AlmerasX., and Le Bras, M. 2003. Fire retardancy effect of migration in polypropylene nanocomposites induced by modified interlayer. Polym. Deg. Stab. 82 379-385. 

Expandable interlayers provide an alternative way for rapid delivery. Migration, even if promoted by an incompatible interlayer, is sometimes not rapid enough to deliver active substances to the surface therefore, a new adaptive concept has been developed recently [53,54], A material utilizing this mechanism contains a phosphorylated polyol (PPOL) interlayer of relatively low decomposition temperature intercalated between layers of nanoparticle. At the early stage of fire action the gaseous degradation products of the interlayer separate the nanolayers and drive them to the surface in the most rapid way. 

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