Studies on a-Cyanoacrylate. IV

In view of the fact that alkyl α-cyanoacrylates are usually prepared by thermal degradation of the corresponding polymers, the degradation of polycyanoacrylates under nitrogen at 230-160°C was investigated by means of a heat balance. The degradation velocity of the polymer decreased in the following order: when anionic polymerization products were used, methyl-> ethyl-> isopropyl-> n-butyl-> cyclohexyl-> 2-ethylhexyl-> isobutyl-; when products obtained from alkyl cyan-oacetes through coudensation with formaldehyde were used, ethyl-> methyl-> cyclohexyl-. The degradation velocities were found to be of the first order of the polymer for the cyclohexyl derivative and of the 1/2 order for the rest of the polymers. The effects of the polymerization degree on the degradation were clarified and the activation energies calculated.