5. Molar mass control

The relationships given in this section can be used to prepare a reaction mixture leading to a polymer with a given molar mass, and possibly to well-defined end groups. Obviously, unforeseen phenomena (secondary reactions, partial or total precipitation of the polymer) may lead to deviations from the values given by these relationships; however, they are valuable insofar as they enable an approximate composition of the reaction mixture to be determined and, consequently, limit the number of preliminary experiments.