An analytical solution of the molecular weight distribution of reversible step growth polymerization in homogeneous continuous flow stirred tank reactors

Mole balance for the molecular weight distribution in homogeneous continuos-flow stirred tank reactors (HCSTRs) for reversible step-growth polymerization has been written. The relation for the moment generating function G is found to be a nonlinear ordinary differential equation and has been solved analytically. The solution of the MWD of the polymer formed is shown to be valid even if the condensation product is removed. At equilibrium, the solution reduces to the Flory distribution. The computations show that the polydispersity of the polymer first increases with the residence time θ of the reactor, but, for large θ, it reduces to the equilibrium value after undergoing a maximum.