Chain Branching in Polychloroprene

FIGURE 12-48 The formation of long chain branches in polychloroprene. 

The function g can now be expressed in terms of X and then for a randomly branched sample g can be obtained from g -g0 6. But by now you re probably lost, so we will back 

The idea is to use the SEC curve to calculate what would be the intrinsic viscosity of the whole sample by summing the intrinsic viscosities of all the individual fractions. This is done by taking each point on the SEC distribution and for each value of V. obtain 

= Mfy], from the universal calibration curve. We have assumed that the intrinsic viscosity of a branched polymer is equal to a branching function g expressed in terms of a parameter A equal to the (number) average number of branch points per unit molecular weight (see Equation 12-68). 

We have presented equations for g = g06 and g previously and substituting we get the following two equations, the first relating J, = for each fraction (Equation 12-69)  

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