Gamma induced changes in the structure and optical properties of ZnS/PVA nanocomposite

Nanocomposite of polyvinyl alcohol (PVA) and zinc sulfide (ZnS) was fabricated by ex situ casting technique. ZnS nanoparticles were prepared by chemical coprecipitation method in air atmosphere using EDTA-ethylenediamine as stabilizing agent. Rietveld refinement of X-ray data showed that the prepared ZnS adapts cubic zinc blend structure with a lattice parameter fits 5.345 angstrom and a mean grain size of 4 nm. Samples from ZnS/PVA nanocomposite have been exposed to gamma doses in the range 0-400 kGy. The effect of gamma radiation on the structural and optical properties of ZnS/PVA has been investigated using XRD and UV-Vis spectroscopy. The absorption spectra confirm the formation of hybridized film ZnS/PVA nanocomposite with refractive index in the range of 1.3123-1.5253 (at 700 nm). Also, the gamma radiation reduces the optical energy gap from 4.58 to 2.75 eV. This could be attributed to the increase in structural disorder of the irradiated ZnS/PVA nanocomposite due to the formation of coordination reaction between OH of PVA and ZnS nanoparticles. This means that the gamma radiation led to a more compact structure of ZnS/PVA nanocomposite and causes proper dispersion of ZnS nanoparticles in the PVA matrix. Further, the Commission Internationale de E'Claire (CIE units x, y, and z) methodology was applied for the description of colored samples. The color intensity Delta E, the color difference between the non irradiated sample and the irradiated ones, was increased from 1.39 to 11.18 with increasing the gamma dose up to 400 kGy. J. VINYL ADDIT. TECHNOL., 25:271-277, 2019. (c) 2018 Society of Plastics Engineers