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In this paper, information is given about the investigation of the dielectric properties of bionanocomposites modified with fish bones (FBs) and scales and metal nanoparticles (Al, Fe) with 50–80 nm dimension before and after ultraviolet (UV) irradiation, depending on the temperature, the irradiation time and the volume content of fillers. The investigations of dielectric permittivity and dielectric loss were carried out in the temperature range 300–390 K, the time of irradiation with UV rays were 50, 100, 70 and 150 h, and the filler contents were 3, 5, 7, 10, 15 vol.% and nanoparticles 1 vol.% Al (Fe).

It was found that the dielectric constant of UV-irradiated biocomposites with FB additives increases and the dielectric loss decreases. An increase in dielectric constant is also observed with an increase in the volume content of a biological origin filler. Note that the effect of UV irradiation causes the appearance of a new region of dielectric loss in the temperature-dependent tan$\delta$ of the polyethylene. However, in modified samples after irradiation, under the same conditions, the change in dielectric properties is much less pronounced than in the initial ones, i.e. the dielectric constant increases monotonically, and the value of tan$\delta$ in the maximum of the new loss region is much smaller. Moreover, the effect of the additive is manifested in slowing down the process of LDPE oxidation in the irradiation zone, since the main losses of the polyethylene are primarily caused by the relaxation of the carbonyl groups. Thus, the observed dependences of $𝜀$ and tan$\delta$ on the time of exposure to UV rays are explained by a change in the physical structure of the polymer matrix and the boundary layer of the components composition under the action of charges formed during irradiation.

This study gives information about the effects of UV (here, the wavelength is 160 nm) exposure on the bulk etch rate ($V_B)$, track etch rate ($V_T)$, the detector sensitivity ($S)$, critical angle (${𝜃}_c)$ and etching efficiency ($\eta )$ of Makrofol-E Solid State Nuclear Track Detector. The effect of UV on the activation energy of Makrofol-E was also studied. Nine pieces of Makrofol-E Solid State Nuclear Track Detector were separated into three equal sets as set A, set B and set C. Set A, named as reference set (Fission fragment FF), was irradiated to ${}^{252}$Cf source. Set B, called as post-exposed ($\mathrm{\text{FF}}+\mathrm{\text{UV}}$), was first irradiated to ${}^{252}$Cf and then exposed to UV. The process was reversed for set C named as pre-exposed ($\mathrm{\text{UV}}+\mathrm{\text{FF}}$) at the same conditions. From the results, it is concluded that radiation produces small but significant effect on activation energy $E_B$ of bulk etch rate for pre-exposed and post-exposed samples. Also, the activation energies $E_T$ of track etch rate for post-exposed and Fission fragment samples are within experimental uncertainty. The energy carried by UV radiation may be responsible for cross networking processes occurring during the exposure which results small change in activation energies for both $E_B$ and $E_T$. The $E_T$ can be increased by hardening detector material of the pre-exposed detector.

The effects of three organic colorants on photo-initiated crosslinking and photo-oxidation degradation of polyethylene (PE) samples irradiated by microwave excited (MWE) UV lamp in the melt and the related mechanism have been studied by gel content and thermal extension rate determinations, X-ray photoelectron spectroscopy (XPS), mechanical property tests, UV spectroscopy, and light microscope. The data from the gel content and thermal extension rate determinations of photo-crosslinked polyethylene (XLPE) samples show that the three colorants can decrease the efficiency of photo-initiated crosslinking of polyethylene to some different degree, in which the effect of red colorant is the largest among the three colorants. The colorized samples of 1 mm thickness are easily to be crosslinked to a satisfactory gel content of about 70% by the MWE lamp and optimized reaction conditions, such as the concentration of colorant, irradiation time, and so on. The XPS results give the evidence that the colorants can accelerate the surface photo-oxidation during the photo-crosslinking of polyethylene. The photo-oxidation products such as -CH₂-O- and -C(C=O)- groups on the surface of XLPE samples with the colorants apparently increase with increasing the irradiation time. The data from the mechanical tests show that the colorants reduce the tensile strength and improve the elongation at break of XLPE samples. All the above results show that the effects of the three colorants on photo-initiated crosslinking and photo-oxidative degradation decrease with the order of red > blue > green colorants. The light microscope photos show that the colorant can disperse well in PE resin. The mechanism of the colorant effects can be elucidated by comparison of the UV absorption spectra of photo-initiator and colorants. This is because the colorants absorb the same UV wavelength regions as photo-initiator, and thus decrease the photo-crosslinking efficiency of photo-initiator and accelerate the surface photo-oxidation of XLPE materials.