Thermodynamics of step-growth polymerization

The number average degree of polymerization for a condensation reaction of a diacid with a glycol 

In such a reaction, the equilibrium being constant, the rate constant is independent of the molecular size. It is, therefore, possible to write. 

The free energy change in step growth condensation, AF = A// — TA5 = RT In K. By plotting In K against reciprocals of absolute temperatures, one obtains roughly a linear relationship. Sawada wrote, therefore, 

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