Comparison of the reactivity of acrylate and methacrylate monomers

The kinetics of the first steps of the polymerization of two model compounds, methyl methacrylate (MMA) and methyl acrylate (MA) monomers in cyclohexane solution were investigated by pulse radiolysis with transient spectroscopic detection. The transient spectra of the two monomers were measured to be very similar with a maxima at about 290nm. The maxima belong to α-carboxyalkyl radical. From the G*ε measured at the maxima ε values were calculated using G=4. Much higher extinction coefficient was calculated for MMA than for MA. This was explained on the basis that the higher level of conjugtion results in a higher extinction coefficient and higher absorbance at MMA. (Author)