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The effect of γ-irradiation on the surface properties of polypropylene (PP) has been studied as a function of the absorbed dose. It has been established that γ-irradiation leads to an increase in the free surface energy of the polymer, its acid–base component, and the surface polarity. An analysis of the IR spectra of γ-irradiated PP samples indicated the formation of oxygen-containing groups in the composition of PP macromolecules, which was confirmed by the values of the surface acidity parameter. An increase in the dose led to an increase in the concentration of products of radiation-induced conversion. A significant increase in the melt flow index (MFI) of polypropylene up to an absorbed dose of 150 kGy also evidenced the occurrence of oxidation and destruction processes. The MFI decreased at radiation doses above 150 kGy, and this fact indicates that such doses of ionizing radiation lead to the predominance of the processes of polymer structuring or crosslinking. [ABSTRACT FROM AUTHOR]

The surface energy characteristics of polyvinylidene fluoride irradiated with accelerated helium ions have been investigated. The bombardment of the polymer with helium ions leads to an increase in the acid–base component of the surface free energy and surface polarity due to the appearance of polar functional groups in the surface layer. Determination of the acidity parameters of the irradiated polymer surface indicates the predominance of acidic functional groups on the surface layer as a result of irradiation. It is likely that a decrease in the dispersion component of the surface free energy with the energy of ions and radiation dose is associated with the carbonization of irradiated polymer surface. [ABSTRACT FROM AUTHOR]

The effect of γ-radiation dose on the surface energy characteristics of commercial polytetrafluoroethylene (PTFE) of five different grades has been studied. In the course of PTFE irradiation in air, radiation oxidation leads to the appearance of functional groups and an increase in the acid–base component of the free surface energy and surface polarity; in this case, the dispersive component of the free surface energy decreases with dose because of the radiation-induced loosening, amorphization, and degradation of the polymer. The effect of γ-irradiation of PTFE on its wetting with aqueous solutions of the anionic surfactant sodium dodecyl sulfate has been studied for the first time. It has been found that irradiation increases the wetting and the work of adhesion of the surfactant solution due to the appearance of polar groups in the surface layer. [ABSTRACT FROM AUTHOR]