Kinetics of Polycycloaddition of Flexible α-Azide-ω-Alkynes Having Different Spacer Length

Two flexible α-azide-ω-alkynes differing in the length of the hydrocarbon spacers (C8 vs. C12) between functional groups are synthesized. Their bulk polymerization kinetics is studied by differential scanning calorimetry (DSC) and parameterized with the aid of isoconversional methodology. The monomer with a shorter hydrocarbon spacer has somewhat greater reactivity. The effect is traced to a moderate increase in the effective value of the preexponential factor that arises from the fact that the respective monomer has a higher initial molar concentration in itself. The techniques of GPC and NMR provide additional kinetic and mechanistic insights into the studied reaction.