Lacik, I.; Beuermann, S.; Buback, M.
Aqueous phase size-exclusion chromatography used for PLP-SEC studies into free-radical propagation rate of acrylic acid in aqueous solution
Macromolecules 2005, 38, 5098-5103.
 

Pulsed laser polymerization (PLP) in conjunction with analysis of the resulting polymer by size-exclusion-chromatography (SEC) was used to measure propagation rate coefficients, k_p, of acrylic acid (AA) in aqueous solution at concentrations of 20 and 40 wt % and temperatures between 2.6 and 28.5 °C. Under these conditions, more than 99% of acrylic acid exists in the nonionized form. The molecular weight distribution (MWD) of poly(AA) is directly measured by aqueous SEC. The k_p values at 20 wt % are about 60% higher than at 40 wt %. The activation energy of k_p is close to 12.0 kJ·mol^-1 at both concentrations. At 25 °C and 20 wt %, k_p of AA in aqueous solution exceeds 100 000 L·mol^-1·s^-1 which is the highest k_p value determined by the PLP-SEC technique so far.