Cross-linking, description

The three levels of structure listed above are also useful categories for describing nonprotein polymers. Thus details of the microstructure of a chain is a description of the primary structure. The overall shape assumed by an individual molecule as a result of the rotation around individual bonds is the secondary structure. Structures that are locked in by chemical cross-links are tertiary structures. 

G Rossi, KA Mazich. Macroscopic description of the kinetics of swelling for a cross-linked elastomer or a gel. Phys Rev E 48 1182-1191, 1993. 

Figure 32 presents the fit of Eq. (63) to the cross-link data. The shaded area displays the constant EISF contribution to S(Q,t). A combined fit to all spectra yields W/4 = 0.84 1013 A4s 1 and rate fixed to the value obtained from the joint fit. The obtained molecular mass melt of linear PDMS chains in very good agreement with the prediction of a 2/f reduction [see Eq. (64)]. 

Early descriptions of the changes in cytoplasmic structure that occurred during pseudopodia formation referred to a soluble (Sol) and a gelled or semisolid (Gel) state. Thus, it was assumed that the cytoplasm in the organelle-free peripheral cytoplasm was in the Sol state, whilst in pseudopodia (which resist deformation by mechanical forces) it is in the Gel state. Thus, the control of neutrophil functions via changes in cytoplasmic structure may be explained by understanding this so-called Sol —> Gel transition. It is perhaps more convenient to think of this transition as the processes that elongate and cross-link actin filaments. 

The second important problem is a kinetical description of intramolecular cross-linking. Kinetic characteristics can vary in wide range depending on the nature of cross-linking agents, properties of the polymeric chain and experimental conditions. ... 

Thus the approach described can be apolied to the description of the kinetics of intramolecular cross-linking and the conformational properties of cross-linked products. 

Ranta H (1978) Age-related changes in collagen cross-linking. Changes in bovine dentine and periodontal ligament and description of a new type of non-reducible cross-link. Proc Finn Dent Soc 74 (Suppl. II), 3-64. 

Swelling tests and determination of tensile properties. The procedure for estimating cross-link density from equilibrium swelling data is described in detail in a previous paper (6). The tensile properties of the PU films were carried out at 23°C and 60% relative humidity. The crosshead speed and distance were 10 mm/min and 30 mm, respectively. A more detailed description of the tensile tests is given elsewhere (6). 

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