Determination of propagation rate constants using a pulsed laser technique

Propagation rate constants (k sub p ) for the polymerization of methyl methacrylate (MMA) and styrene (STY) were determined by using a recently developed experimental technique. The procedure utilized a pulsed laser UV light source for the polymerization, and gel permeation chromatography (GPC) was used to analyze the products. The average k sub p values obtained were 294 plus/minus 9 and 78 plus/minus 6 l mol exp --1 s exp --1 for MMA and STY, respectively at 25 deg C. These k sub p values were found to be independent of chain length ( nu ), initiator type, and concentration. The inclusion of methanol, ethylbenzene (to STY), ethyl acetate (to MMA), or poly-STY at 0.5% w/v as additive to the polymerization mixture had no significant effect on k sub p . Graphs. 16 ref.--AA