Radiation hardening of phenol formaldehyde oligomers

Temperature effect on the radiation hardening of phenolformaldehyde oligomers of the resol type as well as the structure of the polymers prepared are studied. The samples in the form of films placed upon the glass have been hardened using electron accelerator EhlT-1.5 A at the electron energy 1.0-1.1 MeV, the current intensity 7-9 μA and the rate of the absorbed irradiation dose of 0.02-0.03 MGy/s. The hardening of oligomers under the effect of accelerated electrons occurs during continuous heating. During the heating of oligomers up to 120-150 deg for 2-4 min the samples do not harden. Kinetic curves of oligomer hardening and the activation energy of the process are presented