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In this present work, zinc-tin oxide/chitosan hybrid composite was prepared by chemical precipitation method using chitosan as biosurfactant, ZnCl2 and SnCl2 as source materials and sodium hydroxide as precipitating agent. Structural and morphological features of as prepared hybrid composites were studied. Fourier transform infrared (FT-IR) spectroscopy of the hybrid composites revealed that the formation of bond between ZnO, SnO2 and chitosan matrix. X-ray diffraction (XRD) pattern indicates that the sizes of crystallites are in ~ 4.2-27 nm range. From High resolution scanning electron microscopy (HR-SEM) observation, the morphology of hybrid composites forms spherical shape and spherutlite structure. The elemental compositions of (carbon, nitrogen, zinc, tin and oxygen) hybrid composite were confirmed by EDAX analysis. The zinc-tin oxide/chitosan hybrid composite exhibited higher thermal stability than chitosan- ZnO and chitosan-SnO2 composites. Hence it can be used for various applications such as sensing, catalysis, optoelectronic devices and dye removal process. [ABSTRACT FROM AUTHOR]

In this study, chitosan-MgO bio-composite was successfully prepared by simple chemical precipitation method. The bioactive polymer of chitosan (N-deacetylated derivative of chitin) was subjected to action with magnesium oxide modifiers. The functional characteristics of chitosan and MgO were characterized and confirmed by FTIR spectroscopy. From the XRD pattern, crystalline pattern of CS-MgO composite was found to be the semi crystalline nature. The biopolymer connected MgO particles was in rod like structure and confirmed by H-SEM analysis. Thermal characteristics of MgO incorporated chitosan have higher stability than chitosan biopolymer. Thus the result of chitosan-MgO bio composite was demonstrated that the synergistic effect obtained among the two components. Consequently, antimicrobial activity of the components was performed against the microbial pathogens revealed that MgO modified chitosan acts as a better bacterial inhibition activity than MgO. Therefore, Chitosan-MgO bio-composite may be an expectant material for the biomedical applications. [ABSTRACT FROM AUTHOR]

Organic–inorganic materials of chitosan–zinc oxide/polyaniline (CS–ZnO/PANI) composite were prepared via precipitation with a polymerization method and characterized by FT-IR, XRD, EDXS and TEM analysis, thereby providing evidence of composite formation. The size of the prepared CS–ZnO/PANI composite was found to be 100–200 nm, thereby rendering the morphology suitable for biomedical applications. Antibacterial activities of chitosan–ZnO (CS–ZnO), polyaniline (PANI) and CS–ZnO/PANI composites were determined against Gram-positive bacterium, Staphylococcus aureus ( S. aureus ), and Gram-negative bacterium, Pseudomonas aeruginosa ( P. aeruginosa ) and were tested in-vitro at 5–50 μg/mL. Results showed that CS–ZnO/PANI composite had broad-spectrum antibacterial activity that was greatly enhanced in comparison with CS–ZnO. In addition, CS–ZnO/PANI composite has tested fungal strains of Candida albicans ( C. albicans ) and relatively higher activities were observed than the known antibiotics. Finally, the antimicrobial activity of CS–ZnO/PANI composite against established biofilms was also examined and resulted in more than 95% inhibition in biofilm formation. [ABSTRACT FROM AUTHOR]

ABSTRACT Brown seaweed Padina tetrastromatica (PTS)-Zinc oxide (ZnO) composites were prepared by chemical precipitation method. The characteristic peaks of PTS and ZnO were confirmed by Fourier transform infrared spectroscopy. X-ray diffraction study was confirmed the formation of ZnO with hexagonal wurtzite phase. Surface morphology and particle's distribution of ZnO were characterized by scanning electron microscopy. Transmission Electron microscopy image reveals that ZnO nanorods are in the size range of 14-164 nm having uniformly blended with polysaccharide of seaweed. Ultraviolet-Visible absorption spectra indicated the sharp absorption peak at 219 nm and broad absorption peak in the 250-350 nm range. Fluorescence spectra shows the broad blue-violet emissions is around at 380-480 nm. Because of the interaction between polysaccharide and ZnO nanorods/particles, the prepared seaweed-ZnO composite exhibit better antibacterial activity than pure ZnO nanoparticles. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40948. [ABSTRACT FROM AUTHOR]

ABSTRACT In this investigation, the porous structure of polyaniline/MgO (PANI/MgO) composites has been successfully synthesized by in-situ oxidative polymerization method. The as-prepared materials were characterized by Ultraviolet-visible absorption spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The obtained composites, for the first time, are used as an adsorbent for the removal of the sulfonated anionic dye reactive orange 16 (RO) from aqueous solution. The equilibrium adsorption isotherms of RO on the PANI/MgO composites were analyzed by Langmuir and Freundlich models, suggesting that the Langmuir model provides the better correlation of the experimental data and maximum adsorption capacity was found to be 558.4 mg g−1. In addition, adsorption kinetics was followed by both pseudo-first-order and pseudo-second-order, but the latter model matches the results much better than the former one. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40210. [ABSTRACT FROM AUTHOR]

Abstract: We synthesized two composites/hybrid composites with a graphene oxide (GO)/mixed GO–ZnO filler using either a chitin or a chitosan matrix. Fourier transform infrared spectroscopy analysis confirmed that chitin had been converted to chitosan during matrix fabrication because only chitosan, ZnO and GO were shown to be present in the composites/hybrid composites. Raman spectroscopy indicated the display of D and G bands at 1345cm−1 and 1584cm−1, respectively. UV absorption peaks appeared at 260–360nm and 201nm in both hybrid composites, which indicate a strong binding of ZnO within the chitosan–GO sheets. High resolution scanning electron microscopy and atomic force microscopy studies demonstrated that on a molecular scale ZnO was well dispersed in the hybrid composites. Impedance spectroscopy and a four-probe resistivity method were used for room temperature electrical conductivity measurements. The electrical conductivity of the chitin-based GO–ZnO hybrid composites was estimated to be ∼5.94×106 S/cm and was greater than that of the chitosan-based GO–ZnO hybrid composite (∼4.13×106 S/cm). The chitin-based GO–ZnO hybrid composite had a higher optical band gap (3.4eV) than the chitosan-based GO–ZnO hybrid composite (3.0eV). The current–voltage measurement showed that electrical sheets resistance of the chitosan-based composites decreased with formation of ZnO. [Copyright &y& Elsevier]