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Figure 12.12b illustrates the application of gel electrophoresis to protein characterization. In this illustration a cross-linked polyacrylamide gel is the site of the electrophoretic migration of proteins that have been treated with sodium dodecyl sulfate. The surfactant dissociates the protein molecules into their constituent polypeptide chains. The results shown in Figure 12.12b were determined with well-characterized polypeptide standards and serve as a calibration curve in terms of which the mobility of an unknown may be interpreted to yield the molecular weight of the protein. As with any experiment that relies on prior calibration, the successful application of this method requires that the unknown and the standard be treated in the same way. This includes such considerations as the degree of cross-linking in the gel, the pH of the medium, and the sodium dodecyl sulfate concentration. The last two factors affect the charge of the protein molecules by dissociation and adsorption, respectively. Example 12.5 considers a similar application of electrophoresis. 

Change information sharing to medium-high, e.g. communicate capacity planning, IT-integration of supplier, ask supplier for short and middle term plan if convenient, digital links among supply chain partners... 

The rheological behavior of filled systems is influenced by a change in the properties of a polymer medium as a result of adsorption interaction of the particles with the polymer and restriction of the molecular mobility of chain in the adsorption layer. Thus, the viscosity is determined not only by hydrodynamic effects but also by mechanical reinforcement of the matrix as a result of interaction with the filler. It has accordingly been suggested that the relative change in viscosity of the medium, due to interaction, is linked with the shift of Tg towards higher temperatures with increasing filler content. The temperature dependence of the viscosity above Tg may be expressed by the WLF equation in terms of the shift of T... 

The complexity of the phenomenon of adhesion, as well as the diversity of materials capable of adhesive interaction, mean that a whole series of monographs would be required to constitute a comprehensive treatise. The purpose of this paper is more modest. We aim to present simple views on polymer adhesion to readers who are not familiar with this field. We choose to do so on a specific example, namely the adhesion between two cross-linked elastomers (a cross-linked elastomer consists of long, flexible chain-like molecules which are interconnected at various points by cross-links to form a molecular network the polymer medium is locally fluid but the macroscopic flow of the material is prevented by the cross-links). This choice is motivated by a number of reasons (a) the possibility of describing the fracture of the adhesive junction between the two elastomers in terms of a simple model, (b) the existence of controlled experiments that can be compared with the predictions of the model, (c) the possibility of introducing concepts that are of interest for other polymer adhesion problems, and, finally, (d) the fact that adhesion between elastomers is a technologically important field. Several texts on polymer adhesion are avaible (Wu, 1982 Kinloch, 1987 Lee, 1991 Vakula and Pritykin, 1991). A good reference for the results of the last few years is the review article by Brown (1991). 

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