Living poly(α-methylstyrene) near the polymerization line. IV. Extent of polymerization as a function of temperature

We measure the extent of polymerization, Φ, as a function of temperature, T, for living poly(α-methylstyrene) in the solvent tetrahydrofuran, using sodium naphthalide and cesium naphthalide as the initiating species. We compare our measurements of Φ(T) to the theoretical predictions of a mean field model and of a nonmean field model [J. C. Wheeler and P. M. Pfeuty, Phys. Rev. Lett. 71, 1653 (1993)]. We find that both models describe our observations semiquantitatively. The nonmean field model is statistically (but not dramatically) a better description for two of the samples. For the third sample, the mean field description is statistically better, probably because the concentration of monomer/polymer in solvent is the smallest for this sample.