The effect of temperature and solvent on polymer tacticity in free-radical polymerization of styrene and methyl methacrylate was studied by 13C and 1H NMR, respectively. Polystyrene shows a mild syndiotactic tendency (Pm = 0.36 ± 0.02) that is independent of temperature over a wide range (-10 to 120°C), while poly(methyl methacrylate) shows a stronger syndiotactic tendency (Pm = 0.17 ± 0.01 at 30°C) that decreases as temperature is increased (Pm = 0.22 ± 0.02 at 80°C). None of the polymerization solvents studied (bulk, THF, DMF, DMSO, acetonitrile, and acetone) had a significant effect on polymer tacticity in either system. The triad fractions of both polymers showed deviations from the Bernoulli model, implying that the antepenultimate unit affects the propagation reaction.
|Number of pages||8|
|Journal||Journal of Polymer Science, Part A: Polymer Chemistry|
|Publication status||Published - 15 Aug 2013|
- poly(methyl methacrylate)
- radical polymerization
- solvent effects