Kinetic and thermodynamic characteristics of anionic living-equilibrium polymerization for (p-Isopropenylphenethyl)poly(α-methylstyrene) macromonomer

The anionic living-equilibrium polymerization (ALEP) of (p-isopropenylphenethyl)poly(alpha-methylstyrene) macromonomer (PMStM) was studied: PMStM was simultaneously purified and initiated above a ceiling temperature (T(c)) and then propagated below T(c). Three PMStMs (M(n) = 1.77 x 10(3), 3.65 x 10(3), and 5.36 x 10(3)) were prepared by the coupling of poly(alpha-methylstyryllithium) with p-isopropenylphenethyl chloride, and were polymerized to produce polymacromonomers, (PMSt)(m) (m = 9.5, 4.1, and 3.5) by n-BuLi in d(8)-THF at temperatures below -10 degrees C under high vacuum via ALEP. From kinetic studies using a (1)H NMR technique, the propagation rate constant (0.240, 0.110, and 0.079 l mol(-1) s(-1)) at -78 degrees C was found to be proportional to a reciprocal of M(n) of PMStM, and its M, dependence was discussed based on a simple diffusion-controlled theory. The thermodynamic characteristics of Delta H(Mst) (-7.48, -6.73, and -3.82 kJ mol(-1)) and Delta S(Mst) (-26.8, -24.1, and -13.7 J mol(-1) K(-1)) were determined from a kinetic analysis, and their M(n) dependence was also discussed. The T(C) values for the three PMStM, including alpha-methylstyrene, were found to be the same (6.0 degrees C). (C) 2010 Elsevier Ltd. All rights reserved.