Abstract: | By using the expression, kt = A1Ds for the chain termination rate constant (where A1 is a constant and Ds is the diffusion constant of radical chain end), a familiar chain termination rate constant, kt = A2/ηs (where A2 is a constant and ηs is solvent viscosity) was examined with variation of conversion x. It was found that the proportionality of chain termination rate constant and solution viscosity is a valid relation at conversion 0 but is approximate at conversion xc ≥ x > 0. Here xc denotes a critical conversion under the average distance around spherical polymers formed in polymerization solution is zero. At conversions above xc, the inverse relation between chain termination rate constant and solution viscosity is not correct. |