Average molecular weight Terms Links

The degree of cross-linking can be expressed in terms of cross-links per gram or per unit volume. If C is the moles of cross-links per unit volume, n the number of network chains per unit volume, d the density of cross-linked polymer, and Me the number-average molecular weight of the polymer segments between cross-links, then... 

Equation (4-46) predicts that the stress-strain properties of an elastomer that behaves like an entropy spring will depend only on the temperature, the density of the material, and the average molecular weight between cross-links. In terms of nominal strain this equation is approximately... 

Neutral cross-linked hydrogels are commonly described in terms of the polymer volume fraction in the swollen and unswollen state and the number average molecular weight of the polymer chain between adjacent cross-links. The difference between polymer volume fractions can be determined from the swelling ratio of the gel (Figure 16.9) [63]. 

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