Gamma irradiation effects on conductivity and dielectric behaviour of PEO-based nano-composite polymer electrolyte systems

Modification of thermal and electrical characteristics of hybrid polymer nanocomposites through gamma irradiation for advanced applications

In this article, we present a straightforward in-situ approach for producing Ag NPs incorporated in graphene oxide (GO) blended with glutaraldehyde (GA) cross-linked polyvinyl alcohol (PVA) matrix. Samples are γ-irradiated by doses of 2, 5, and 10 kGy and in comparison with the pristine films, the thermal conductivity ('k') and effusivity are measured. 'k' decreases with irradiation doses up to 5 kGy and further increase in the dosage results increase in 'k'. We performed FDTD modeling to verify the effect of polarization and periodicity on the absorptivity and emissivity spectra that are correlated to the 'k' and effusivity, empirically. Hence, we can confess that the structural properties of the prepared hybrid nanocomposite are manipulated by γ-irradiation. This attests that the PVA/GO-Ag/GA nanocomposite is radiation-sensitive and could be employed for thermal management systems. Moreover, their strong electrical insulation, as the measured dc conductivity of the γ-irradiated samples is found to be in the range of 2.66 × 10-8-4.319 × 10-7 Sm-1, which is below the percolation threshold of 1.0 × 10-6 Sm-1, demonstrates that they are excellent candidates for the use of thermal management materials. The low 'k' values allow us to use this promising material as thermal insulating substrates in microsensors and microsystems. They are also great choices for usage as wire and cable insulation in nuclear reactors due to their superior electrical insulation.

Influence of 25 MeV Si ions and 25 MeV O ions on the chemical and structural properties of PEEK films

Poly (ether ether ketone) (PEEK) material can be used in a wide variety of fields, such as the aerospace, automotive, electronics, and nuclear industries. In this research, the irradiation effect of 25 MeV Si ions and 25 MeV O ions on the PEEK films was studied, focusing on the changes in chemical and structural properties. By analyzing surface morphology and microstructure evolution of the PEEK films after 25 MeV Si ion and 25 MeV O ion irradiation, particles were generated on surface of the PEEK after 25 MeV Si ion irradiation and black dots were generated on surface of the PEEK after 25 MeV O ion irradiation. The irradiation reduced the surface roughness of the PEEK films from the atomic force microscopy (AFM) results. The Fourier transform infrared (FTIR) results indicated that the groups and structure of the material were not changed by irradiation. The X-ray photoelectron spectroscopy (XPS) results showed that the contents of the chemical bonds C–C, C=O increased first and then decreased with the increasing of the fluences. The generated free radicals were observed by the electron paramagnetic resonance spectroscopy (EPR) at room temperature and the irradiation degradation mechanisms were analyzed. Thermal properties of the PEEK irradiated by 25 MeV O ions, indicating that a new secondary crystallization peak was found during the cooling stage. Consequently, the low fluences irradiation improves in the viscoelasticity and mechanical properties of PEEK films, while the high fluences irradiation reduces its performance.