Entangled polymer networks

In an entangled polymer network the interchain length (i.e., mesh or pore size) can be assessed by determining the correlation length ( ) (Doi and See 1995 Graessley 2004), which for linear polymers with cylindrical Kuhn segments such as mucins can be approximated by the following expression ... 

An important role in the present model is played by the strongly non-linear elastic response of the rubber matrix that transmits the stress between the filler clusters. We refer here to an extended tube model of rubber elasticity, which is based on the following fundamental assumptions. The network chains in a highly entangled polymer network are heavily restricted in their fluctuations due to packing effects. This restriction is described by virtual tubes around the network chains that hinder the fluctuation. When the network elongates, these tubes deform non-affinely with a deformation exponent v=l/2. The tube radius in spatial direction p of the main axis system depends on the deformation ratio as follows ... 

Capillary sieving electrophoresis (CSE) — An electrophoresis technique, in which analytes are separated in a capillary, containing a sieving medium (e.g., an entangled polymer network) in the -> supporting (background) electrolyte. The separation is based on differences in size and shape of the charged analytes. 

Replaceable Gels (entangled polymer networks) linear polyacrylamide, methyl cellulose, hydroxypropylmethyl cellulose, hydroxy-ethylcellulose, polyethylene oxide, polyvinyl alcohol, agarose... 

Arteca, G.A. (1999). Path-Integral Calculation of the Mean Number of Overcrossings in an Entangled Polymer Network. J.Chem.Inf.Comput.ScL, 39,550-557. 

Therefore, it is well established that topological entanglements dominate and control the modulus of polymer networks with long network strands. The Edwards tube model explains the non-zero intercept in plots of network modulus against number density of strands (see Figs 7.11 and 7.12). The modulus of networks with very long strands between crosslinks approaches the plateau modulus of the linear polymer melt. The modulus of the entangled polymer network can be approximated as a simple sum. 

Arteca, G.A. (1999) Path-integral calculation of the mean number of overcrossings in an entangled polymer network. /. Chem. Inf. Comput. Sci., 39, 550-557. 

Additionally, in the enclosed capillary format, vinlike the traditional slab gel format, physically rigid gels are not required. Thus, separation of large molecules in solutions of entangled polymer networks is possible for some apphcations [59],... 

CGE Differences in size and charge (but not size-to-charge ratio) by migration through a gel matrix or entangled polymer network with a range of pore sizes DNA fragments SDS proteins Macromolecules... 

From their studies and those of others, Kramer and co-workers concluded that the drawing of craze fibrils is basically a nano-scale variant of the plastic drawing of fibers and bars of polymer considered in Chapter 10 (Kramer 1983). This drawing behavior is that of an entangled polymer network in which the... 

ZE in sieving media (gels and entangled polymer networks) - based on size-dependent retardation of electromigration of proteins by the medium matrix ... 

Polymers can form materials that are purely elastic, viscoelastic, or viscous, and an entangled polymer network is a good example of this phenomenon. Different relaxation times result from the different kinds of mechanical deformation that can take place in the material. On very small length scales, the bonds between atoms in a polymer chain can be stretched. This deformation relaxes back to its equilibrium state quickly. In the same material on a larger, molecular level length scale, the elastic network itself can be deformed but in this case will relax back to equilibrium slowly as polymer chains must move around each other in the network. 

Eqnation 9.51 differs from the result of ideal rubber elasticity presented below by a factor of 4/5. The reasons for this factor are complexities in the model [19] that are beyond the scope of this text, but one would expect a factor of less than unity becanse of chain ends that do not contribute to the elasticity of the entangled polymer network. Given that the plateau modulus is independent of molecular weights, M, for M > Me, the value of in Equation 9.51 is a constant for a given melt but will vary from polymer to polymer depending on the structural properties of the polymer such... 

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