Propagation Rate Coefficient of Vinyl neo-Decanoate by Pulsed Laser Polymerization

The propagation rate coefficient ( k p ) for vinyl neo -decanoate has been measured by pulsed laser polymerization (PLP) over the range −21 to +21 °C. The Mark−Houwink−Sakaruda constants required for GPC analysis were obtained using size-exclusion chromatography with an on-line viscosity detector, whose analysis required careful quantification of the uncertainties. The data, which satisfy various consistency tests for PLP (invariance of k p to laser pulse frequency, etc.), fit the relation k p (dm 3 mol -1 s -1 ) = 10 7.31 exp(−22.2 kJ mol -1 / RT ); the joint confidence region for these Arrhenius parameters is also given. These Arrhenius parameters are close to those for vinyl acetate [10 7.16 exp(−20.7 kJ mol -1 / RT )]; the small differences between these Arrhenius parameters are, however, statistically significant at the 95% confidence limit. The vinyl neo -decanoate used is actually a mixture of isomers: CH 2 CHOCOCR 1 R 2 CH 3, where the total number of carbons in R 1 and R 2 is 7; however, theory suggests that the k p values for all these isomers should be very similar and polymerization of the mixture can be treated as a homopolymerization with a k p equal to the average k p .