Interphase parameter

Table 7.6 Ranges of important intra- and interphase parameter values for gas-solid and liquid-solid reactions (Carberry, 1976)...

Table 6.6 Ranges of Important Intra- and Interphase Parameter Values for Gas-Solid and Liquid-Solid Reactions...

Naim and Liu [96] used a Bessel-Fourier series stress function and added polynomial terms to provide a nearly exact solution to the stress transfer fixim the matrix to a fragmented fiber through an imperfect interphase. This solution satisfies equilibrium and compatibility every place and satisfies exactly most boundary conditions with the exception of the fiber axial stress. They also proposed the use of an interphase parameter, Ds, and provide a physical interpretation as ... 

The performance of a product where adhesion plays a role is determined both by its adhesive and cohesive properties. In the case of silicones, the promotion of adhesion and cohesion follows different mechanisms [37]. In this context, adhesion promotion deals with the bonding of a silicone phase to the substrate and reinforcement of the interphase region formed at the silicone-substrate interphase. The thickness and clear definition of this interphase is not well known, and in fact depends on many parameters including the surface physico-chemistry of... 

The adhesion promotion of an organic matrix to an inorganic substrate using a silane has been studied to model the structure of the created interphase [64-66]. The polymer/silane interphase is influenced by the solubility parameter of both the silane coupling agent and the polymer. More interdiffusion occurs when the solubility parameters of the polymer and the silane closely match together. It is believed that this model can be applied to silicone adhesive/solid substrate system. 

Lipatov et al. [116,124-127] who simulated the polymeric composite behavior with a view to estimate the effect of the interphase characteristics on composite properties preferred to break the problem up into two parts. First they considered a polymer-polymer composition. The viscoelastic properties of different polymers are different. One of the polymers was represented by a cube with side a, the second polymer (the binder) coated the cube as a homogeneous film of thickness d. The concentration of d-thick layers is proportional to the specific surface area of cubes with side a, that is, the thickness d remains constant while the length of the side may vary. The calculation is based on the Takayanagi model [128]. From geometric considerations the parameters of the Takayanagi model are related with the cube side and film thickness by the formulas ... 

The Takayanagi model parameters are related with filler concentration and interphase thickness by the following simple relationships ... 

Regime-IV flow patterns are of pragmatic interest when interphase heat and mass transfer are of key importance because the existence of the discrete phase generates a large interfacial area per unit tube volume. Evaluation of the interfacial area is made difficult because the bubbles or drops of the discrete phase are usually not of uniform size or shape. By assuming a characteristic size and shape for the drops or bubbles, the interfacial area and the other parameters can be estimated with reasonable accuracy for many situations. 

Depending on values of parameters b and b2, it is possible to distinguish three limiting regimes of the interphase copolymerization... 

The values of this parameter are extensively reported in the literature for many monomers [80]. Using expressions (Eq. 80), it is easy to note that the overall number of moles of monomers being polymerized in unit time in a reaction system is proportional to the interphase surface of the miniemulsion. 

By virtue of the conditions xi+X2 = 1>Xi+X2 = 1, only one of two equations (Eq. 98) (e.g. the first one) is independent. Analytical integration of this equation results in explicit expression connecting monomer composition jc with conversion p. This expression in conjunction with formula (Eq. 99) describes the dependence of the instantaneous copolymer composition X on conversion. The analysis of the results achieved revealed [74] that the mode of the drift with conversion of compositions x and X differs from that occurring in the processes of homophase copolymerization. It was found that at any values of parameters p, p2 and initial monomer composition x° both vectors, x and X, will tend with the growth of p to common limit x = X. In traditional copolymerization, systems also exist in which the instantaneous composition of a copolymer coincides with that of the monomer mixture. Such a composition, x =X, is known as the azeotrop . Its values, controlled by parameters of the model, are defined for homophase (a) [1,86] and interphase (b) copolymerization as follows... 

Fig. 9 Evolution with conversion p of composition distribution of the products of interphase copolymerization calculated at the initial monomer mixture composition x° = 0.6 and parameter a (Eq. 100) equal to 0.3...

Since the membrane water partition coefficient is a relevant parameter for the pharmacokinetic behaviour, i.e. drug uptake, many more studies on the speciation of drugs at membrane interphases can be found in the... 

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