Peculiarities of chemical etching of polyethylene terephthalate irradiated with radiations of various linear energy transfer (let)

Polyethylene terephthalate (PETP) in the form of films of various thicknesses has been irradiated with 60Co gamma-rays, deuterons (13 MeV) and alpha particles (23 MeV) and then subjected to chemical etching in aqueous solutions of potassium hydroxide of various compositions. It has been shown that under the action of radiations of linear energy (LET) in the interval from 0.2 to 50 keV/μ the composition of polymer chemical etching products is the same. The etching rate of gamma-irradiated PETP increases linearly with absorbed dose from 1 to 100 Mrad. For samples irradiated with charged heavy particles, a maximum has been observed on the etching rate vs. dose curve in the 5-15 Mrad region, whereby the greater the LET radiation the greater the polymer etching rate at the maximum. A change of temperature from 65 deg to 95 deg C and also of solution alkali concentration from 1 to 6 M increases the etching rate of the initial as well as the irradiated PETP. The calculated effective enero.y of activation of the etching process is equal to 17 and 19.7 kcal/mole for non-irradiated and irradiated polymer, respectively. Additions of ethylene alcohol accelerate, and additions of surfaceactive substances retard, the etching rate