Front factor cross-links

Here, E is the Young modulus in the rubbery state, d the density, R the gas constant, T the temperature in K, Mc the molecular weight between crosslinks, q the cross-linking density, and tp the front factor. The value of tp is close to unity. 

Pass to determination of front-factor. Since for densely cross-linked polymers it is valnes increase with growth of mesh s points freqnency by linear law in range 0.650.85 [3], so... 

In view of the fact that front factor s values for cross-linked polymers grow linearly with increase of the mesh points concentration within limits 0.650.85 [3], will Old the following calculating equation ... 

Here, F is the force per unit original (undeformed) cross-sectional area of the swollen network, 0 is a front factor (= 1), a is the elongation ratio, and and T are Boltzmann s constant and the absolute temperature, respectively. From the tensile stress-strain curves and Eq. (1), N and the number of crosslinked chains per clay sheet were calculated for NC gels with different Cday [40]. The results revealed that neighboring clay sheets in NC gels are linked by at least tens of flexible polymer chains (a few tens to more than 100). 

For a perfect phantom network of functionality/, the front factor contains the term (f - 2)1 f, leading to equation (9.71), which considers chemical crosslinks of arbitrary functionality, but no physical cross-links. 

A sample of elastomer, cross-linked at room temperature, is swollen afterward to 10 times its original volume. Then it is stretched. What value of the front factor should be used in the calculation of the stress ... 

This gave the necessary link to the parameters of the theoretical models. The cross correlation represent the collective motion around the solute and as such are very difficult to incorporate into a model based on molecular properties. In the theoretical models for the electrostatic mechanism, the cross correlation was simply introduced as a scaling factor in front of the self EFG-TCF [37]. This scaling factor, however, contains information which is essential for understanding the relaxation mechanism. 

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