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 Å 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 ΔE, 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.

Nanocomposite films of polymethylmethacrylate PMMA with Sn0.75Fe0.25S2 nanoparticles (NPs) were fabricated by both thermolysis and casting techniques. Changes in PMMA/Sn0.75Fe0.25S2 nanocomposite (NCP) due to gamma irradiation have been measured. XRD results indicate that the gamma doses of 10–80 kGy cause intermolecular crosslinking that reduces the ordered portion in the NPs. Bonding between the NPs and the host PMMA was confirmed by FTIR. TGA results indicate an enhancement in thermal stability in the NCP films irradiated with doses 20–80 kGy. The optical band gap was reduced from 3.23 to 2.47 eV upon gamma irradiation up to 80 kGy due bonding between the NPs and PMMA which enhanced the amorphous part of the NPs. Finally, the color variation between the blank and irradiated films (ΔE) was determined. Color changes immensely when the PMMA/Sn0.75Fe0.25S2 NCP films are gamma irradiated. Values of ΔE were as much as 31.6 which is an acceptable match in commercial reproduction on printing presses.

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Polyvinyl alcohol/lignosulfonate (PVA/LS) composite films have been prepared using casting technique. The effect of lignosulfonate concentrations (0.001, 0.005, 0.01, 0.05, 0.1 and 0.5 wt %) on the optical and structural properties of polyvinyl alcohol (PVA) has been investigated using UV-vis spectroscopy and X-ray diffraction. The results indicate that, the addition of LS led to a more compact structure of PVA, which resulted in an increase in its refractive index and amorphous phase. This was associated with a reduction in the optical energy gap that could be attributed to the increase in disorder structural of the composites. Moreover, the transmittance of PVA/LS composite film decreased with the increase of LS doping concentrations onto the PVA matrix. The results reflect the proper dispersion of LS in the PVA matrix that causes a strong intermolecular interaction between LS and PVA suggesting strong hydrogen bond formation between the hydroxyl group in PVA chains and the outer site groups of LS. Further, the transmission of the samples in the wavelength range of 370-780 nm, as well as any color changes, was studied. The color intensity ΔE, which is the color difference between the pure PVA sample and those with different LS concentration, increases with increasing the LS content and was accompanied by an increase in the yellow and red color components. J. VINYL ADDIT. TECHNOL., 25:85-90, 2019.