Propagation rate coefficients for styrene solution polymerization in dimethyl formamide and acetonitrile

The technique of pulsed-laser polymerization was used to measure the propagation rate coefficient (k(p)) of styrene in dimethyl formamide and acetonitrile over a range of monomer concentrations at 40 degrees C. A significant solvent effect was observed in both solvents. In dimethyl formamide, the k(p) value systematically falls, as the monomer concentration decreases, to a value that is (at 1 mol l(-1) of styrene) approximately 75% of the bulk k(p). In acetonitrile, the k(p) is also reduced. In this case, however, the k(p) value has a minimum at an intermediate dilution. (C) 2000 Elsevier Science Ltd. All rights reserved.