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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]

The effect of γ-radiation on the gel-forming capability of a Carbomer 140 crosslinked acrylic polymer has been investigated. It has been found that an increase in the radiation dose led to a decrease in the gel-forming capability. Based on IR-spectroscopic data and the results of rheological studies, it has been shown that irradiation of the polymer causes its partial degradation, leading to a decrease in the viscosity of gels and the impossibility of their formation at high radiation doses. Formulations of antibacterial gel compositions have been developed using a radiation-modified Carbomer. [ABSTRACT FROM AUTHOR]

Energy characteristics of the irradiated surface of a polytetrafluoroethylene film depend on the energy and fluence of bombarding MeV protons. Irradiation with 2-4 MeV protons leads to an increase in the surface free energy; 4 MeV protons at a fluence of 1015 proton/cm2 increase the polarity of the polymer surface by 40 times due to the appearance of functional groups, the polarity enhancement being manifested in an increase in the acid-base component of the surface energy by more than a factor of 50. There is a correlation between the dispersion component of the surface energy and the degree of crystallinity of the near-surface layer of the polymer a period. They both grow symbatically in the case of bombardment with 1-2 MeV protons and decrease upon irradiation with 4 MeV protons. It has been found that dehydrofluorination results in carbonization of the irradiated surface, a decrease in the fluorine content, and an increase in the proportion of oxygen due to oxidation of the radicals generated by proton bombardment. [ABSTRACT FROM AUTHOR]

The irradiation of low-density polyethylene with MeV protons leads to a substantial increase in surface free energy, its acid-base component, and surface polarity due to the appearance of functional groups in the surface layer, as confirmed by ATR IR and Raman spectra. It has been shown that the surface energy of the irradiated polymer depends little on the change in proton energy from 1 to 4 MeV at a fluence of 1015 proton/cm2. It has been found that the oxygen content of the irradiated polymer surface increases as a result of oxidative reactions of the radicals generated during radiolysis and the thermal stability of the polymer decreases. [ABSTRACT FROM AUTHOR]

The action of accelerated 1–4-MeV protons on polychlorotrifluoroethylene in vacuum was accompanied by a preferential rupture of the main polymer chain with the release of more than 30 gaseous products, most of which were tetrafluoroethylene and chlorine- and fluorine-containing compounds. As a result of proton bombardment, the concentration of carbon on the polymer surface decreased and the concentrations of fluorine and chlorine increased. It has been shown that the incorporation of chlorine atoms into the structure of a perfluoropolymer changes the mechanism of its proton bombardment and helps to protect its macromolecule from the reaction of fluorine abstraction by accelerated protons with the formation of hydrogen fluoride. It has been found that irradiation with accelerated protons leads to changes in surface energy characteristics. [ABSTRACT FROM AUTHOR]