Gamma Irradiation Synthesis and Influence the Optical and Thermal Properties of Cadmium Sulfide (CdS)/Poly (Vinyl Pyrolidone) Nanocomposites

Abstract

<b>Problem statement:</b> Gamma irradiation has been successfully used to prepare a spherical cadmium sulfide CdS/Poly Vinylpyrolidone (PVP) quantum dots nanoparticles with enhancement of their optical band gap energy and thermal properties at room temperature and under ambient pressure. Sodium thiosulfate was used as a sulfur source in an aqueous solution. The formation of lower band gap energy of CdS/PVP nanoparticles and thermal stability can be controlled by using different irradiation doses. TEM images showed that the CdS/PVP particle size tends to be smaller and with better distribution as irradiation dose increases. <b>Approach:</b> Gamma (γ) irradiation offered many advantages for the preparation of metal nanoparticles by producing large number of hydrated electrons during γ-ray irradiation, which can reduce the metal ions to zero valiant metal particles. <b>Results:</b> CdS/PVP nanoparticles were successfully prepared in one-step by γ-irradiation technique in an aqueous system at room temperature and under ambient pressure. The particle size was found to be less than 10 nm based on the Transmission Electron Microscopy (TEM) that depended on the irradiation doses value, which showed a well distribution with a controlled size as doses change. The presence of PVP polymer was considered an important reason that influenced the shape and the distribution of those nanoparticles. The optical band gap energy of those nanoparticles was calculated by using the UV-VIS absorption spectra. Thermal analysis TGA showed that the composite had a higher degradation temperature than the PVP alone. A possible mechanism of the formation of cadmium sulfide by irradiation system was proposed. <b>Conclusion:</b> This result indicated that CdSO₄ can effectively dope PVP and enhance the optical and thermal properties. In addition, γ-irradiation is an effective technique for preparing inorganic/organic nanocomposites

Structural and Optical Properties of Li&lt;sup&gt;+&lt;/sup&gt;: PVP &amp; Ag&lt;sup&gt;+&lt;/sup&gt;: PVP Polymer Films

“…A strong exothermic peak at 380˚C, 431˚C in the DTA curve corresponds to the decomposition temperature of PVP is well above the heating temperature employed in the present work. tion of silver particles and this strong exothermic peaks at 430˚C and 531˚C in the DTA curve corresponds to the decomposition temperature of PVP is well above the heating temperature employed in the present work respectively [25]. This shows that the thermal stability of the polymer is improved due to the presence of Ag as filler.…”

Formation Mechanism and Characterization of PANI Nanoparticles by Hybrid Chemical and Gamma Irradiation Technique

“…Nuclear radiation is ionizing, which on passage through matter, gives positive ions, free electrons and free radicals and excited molecules (Gasaymeh et al, 2010a). In addition, ionizing radiation also; all the valent metal can be reduced to zero (Gasaymeh et al, 2010b).…”

“…The neighboring PANI molecules thus enhancing the electrical conductivity of the composite can capture these radiolytic products (Chi et al, 1992). Ionizing irradiation of polymer causes chain scission, cross linking and change in their chemical constitution, structure and composition formation of C=C, formation of alkyne's groups, depletion of heteroatom, e.g., N, S or O (Gasaymeh et al, 2010a;2010b;Khanna et al, 2005;Ravinder et al, 2008;Virk et al, 2001). Fig.…”

“…Because positive charges localized on neighboring nitrogen atoms increase the total energy of the polymer system, electron density tends to undergo redistribution; as a consequence, "unpairing" of the lone electron pair of nitrogen atoms occurs without any change in the amount of electrons in the system (Boeva et al, 2014;Heeger Alan, 2001;Mott and Davis, 1997). The exposure of polymers to γ-radiation induces structural defects and degradation of initial structure by scission and emission of atoms, molecules and molecular fragments (Gasaymeh et al, 2010a;2010b;Khanna et al, 2005;Ravinder et al, 2008;Virk and Srivastava, 2001). It generates a number of charged species, ions and free radicals and induces either scission or cross-linking or both.…”

Dielectric Properties of Ni_0.2Zn_0.8Fe₂O₄-Polypropylene Composites

“…However, the shrinkage mismatch after solidstate sintering or brittle properties may seriously influence the performance and durability of the final product. On the other hand, polymer-based composites with high permittivity were proposed due to their flexibility and ability to be easily fabricated into various shapes (Yang et al, 2008;Khor et al, 2009;Rittidech and Khotsongkram, 2006;Gasaymeh et al, 2010).…”