Intramolecular Reaction in Polycondensations. I. The Theory of Linear Systems

For three types of linear polycondensing systems, equilibrium molecular size distributions, including rings as allowable species, are derived. Average molecular weights and amounts of ring and chain fractions are calculated therefrom. The fractions of rings are shown to increase with dilution, and with molecular weight. It is shown that beyond a critical dilution it is sometimes possible to obtain 100 percent yield of rings by driving the condensation to completion. Detailed calculations are made for two important cases corresponding to condensations of the decamethylene glycol-adipic acid type: (1) for equimolar amounts of the two monomers, and (2) unequal amounts, with one monomer type completely reacted.