5. Methods for characterizing cross-linking density

5.1 From information on chemical structure

In a number of cases, it is possible to obtain reliable information on the structural state and, in particular, on the progress of the polymer's crosslinking process. This information can be obtained from measurements:

• by differential scanning calorimetry (reaction enthalpy) ;

• by infrared (IR) spectrophotometry (determination of residual reactive groups) ;

• nuclear magnetic resonance (NMR) (same assays).

We can then make assumptions about the current network structure, write down the corresponding UCR and determine the cross-linking density by calculation.