Kinetic and thermodynamic characteristics of anionic living-equilibrium polymerization for (p-Isopropenylphenethyl)poly(α-methylstyrene) macromonomer
✍ Scribed by Kazunori Se; Masaaki Suzuki
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 718 KB
- Volume
- 51
- Category
- Article
- ISSN
- 0032-3861
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✦ Synopsis
and thermodynamic characteristics of equilibrium polymerization a b s t r a c t
The anionic living-equilibrium polymerization (ALEP) of (p-isopropenylphenethyl)poly(a-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 ¼ 1.77 Â 10 3 , 3.65 Â 10 3 , and 5.36 Â 10 3 ) were prepared by the coupling of poly(a-methylstyryllithium) with p-isopropenylphenethyl chloride, and were polymerized to produce polymacromonomers, (PMSt) m (m ¼ 9.5, 4.1, and 3.5) by n-BuLi in d 8 -THF at temperatures below À10 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 À1 s À1 ) at À78 C was found to be proportional to a reciprocal of M n of PMStM, and its M n dependence was discussed based on a simple diffusion-controlled theory. The thermodynamic characteristics of DH MSt (À7.48, À6.73, and À3.82 kJ mol À1 ) and DS MSt (À26.8, À24.1, and À13.7 J mol À1 K À1 ) were determined from a kinetic analysis, and their M n dependence was also discussed. The T C values for the three PMStM, including a-methylstyrene, were found to be the same (6.0 C).