Synthesis of Polymer Nanocomposites Based on [Methyl Cellulose](1-x):(CuS)x (0.02 M ≤ x ≤ 0.08 M) with Desired Optical Band Gaps

In this paper, the sample preparation of polymer nanocomposites based on methyl cellulose (MC) with small optical bandgaps has been discussed. Copper monosulfide (CuS) nanoparticles have been synthesized from the sodium sulphide (Na₂S) and copper chloride (CuCl₂) salts. Distinguishable localized surface resonance plasmon (LSRP) absorption peaks for CuS nanoparticles within the 680⁻1090 nm scanned wavelength range were observed for the samples. An absorption edge (Ed) was found to be widely shifted to a lower photon energy region. A linear relationship between the refractive index of the samples and the CuS fraction was utilized to describe the distribution of the particle. The optical bandgap of MC was reduced from 6.2 to 2.3 eV upon the incorporation of 0.08 M of CuS nanoparticles. The optical dielectric loss, as an alternative method, was used successfully to estimate the optical bandgap. Moreover, the electronic transition type was identified by using Tauc's extrapolation method. The plots of the optical dielectric constant and energy bandgap as a function of the CuS concentration were utilized to examine the validity of the Penn model. For the nanocomposite samples, the Urbach energy was found to be increased, which can be evidence for a large possible number of bands-to-tail and tail-to-tail transitions. However, from the X-ray diffraction (XRD) analysis, it was also found that the synthesized CuS nanoparticles disrupted the crystallinity phase of the MC polymer. Finally, fourier transform infrared (FTIR) spectroscopy for the samples was also performed. Significant decreases of transmittance intensity as well as band shifting in the FTIR spectra were observed for the doped samples.

Synthesis, characterization, and debromination reactivity of cellulose-stabilized Pd/Fe nanoparticles for 2,2',4,4'-tretrabromodiphenyl ether

In this study, two kinds of cellulose derivatives (polyanionic cellulose (PAC) and hydroxypropylmethyl cellulose (HPMC)) were selected as stabilizers of Pd/Fe nanoparticles (NPs) to investigate their influences on the debromination performances of 2,2',4,4'-tretrabromodiphenyl ether (BDE47). Field emission scanning electron microscope (FE-SEM) images revealed that the cellulose-stabilized Pd/Fe NPs were smaller and more uniform than the bare-Pd/Fe NPs. X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS) results suggested that cellulose coatings found on Pd/Fe NPs surfaces featured some antioxidation abilities, which followed the order of HPMC < PAC. Sedimentation tests demonstrated that the stabilizing power of PAC for Pd/Fe NPs was higher than that of HPMC. Fourier transfer infrared spectrometer (FTIR) results indicated that PAC molecules were bound to the Pd/Fe NPs surfaces by polar covalent bonds and hydrogen bonds, while HPMC molecules interacted with the nanoparticles by hydrogen bonds. Batch debromination test for BDE47 demonstrated that the catalytic debromination rate with cellulose-stabilized Pd/Fe NPs was higher than that with bare-Pd/Fe NPs during reaction period of 15 min. Overall, this study indicated that both celluloses are beneficial to forming smaller, more regular, stable and antioxidative Pd/Fe NPs, leading to higher debromination reactivity for BDE47 compared with the bare-Pd/Fe NPs. Therefore Pd/Fe NPs can be utilized as a promising remediation technology for the contaminated groundwater and soils.

Stabilization of ZnS nanoparticles by polymeric matrices: syntheses, optical properties and recent applications

ZnS nanocomposites is a promising area of research for designing novel functional hybrid materials due to their unique optical and electronic properties. This review emphasizes on the synthesis, optical studies and potential applications.