Effect of aryl substituents on the reactivity of phenyl carbamate acrylate monomers

Novel monoacrylate monomers with a carbamate secondary functionality and a terminal aryl group were synthesized to study the mechanisms that allow for increased reactivity of these monomers compared to that of typical monoacrylate monomers. Systematic studies were conducted by varying electron-withdrawing and electron-donating substituents on the aryl moiety. Two primary hypotheses were studied, which were that resonance and electronic effects or hydrogen-bonding effects lead to enhanced reactivity. Kinetic evaluations of these substituted monomers revealed that electronic and resonance effects are not. the primary source of the increased reactivity. Moreover, correlations of dipole moment calculations with steady-state polymerization rate behavior revealed that dipole moment is also not the primary source of the increased reactivity. However, comonomer studies showed that, by adding the novel monoacrylate monomers to more slowly polymerizing traditional acrylate monomers, the overall reactivity of the mixture could be increased dramatically, revealing a possible use as reactive diluents. Additionally, hydrogen-bonding strength was analyzed and correlated with steady-state polymerization rate behavior. The hydrogen-bonding and N-H polarization strength of the monomers is not the primary source of the increased reactivity.