PVC FILM BEHAVIOR UNDER PROTON BOMBARDMENT

摘要

Thin films of poly(vinyl chloride) (PVC) were bombarded with protons of energies between 0.7 and 3 MeV, and the loss of mass was studied using back- and forward-scattering techniques. The abundances of chlorine, carbon and hydrogen were measured simultaneously during the bombardment. With fluences up to 8 x 10~(15) protons/cm~2, the amount of carbon does not change, but chlorine is strongly depleted (G -value = 3) and hydrogen is reduced to between 70 and 80%. This is consistent with the process of dehydrochlorination. An immediate preference is observed for producing this type of chemical reaction over others, suggesting that excitation energy is deposited in a small region like the monomer unit, and then distributed according to the chemical properties of the region.