Investigation of γ-irradiated polyvinylidene fluoride and its acute toxicity

Polyvinylidene fluoride (PVDF) is an industrial polymer with many applications. The EPR spectrum of polyvinylidene fluoride (PVDF) irradiated by gamma-rays at low temperature (-196 degrees C) provides evidence for the presence of radicals formed by loss of a fluorine atom from PVDF, and polyenyl radicals. Polyenyl radicals dominate in the polymer irradiated at room temperature. Peroxide radicals formed as a result of oxidation of primary free radicals by atmospheric oxygen are observed in the EPR spectrum of a polymer irradiated in air, or when air is introduced to a polymer irradiated in a vacuum. Carbonization and oxidation of gamma-irradiated PVDF were observed in the XPS spectrum. A model for polymer degradation based on correlated G3(MP2) molecular orbital theory electronic structure calculations is described. The presence of HF in the products and a low yield of products with the composition CxFyHz indicate the absence of noticeable thermal destruction of the main polymer chain upon heating to 220 degrees C of both the initial and gamma-irradiated PVDF. Although any HF released during the PVDF dehydrofluorination would be toxic, a study of the acute toxicity of gamma-irradiated PVDF showed that the polymer does not exhibit toxicity after a single intragastric route of administration to mice.

Automated summary

Polyvinylidene fluoride (PVDF) forms various radicals during irradiation, with a low amount of HF in the thermal degradation products, indicating minimal impact on the main polymer chain. Acute toxicity study shows that γ-irradiated PVDF is not toxic to mice.