Novel Recovery of Nano-Structured Ceria (CeO(2)) from Ce(III)-Benzoxazine Dimer Complexes via Thermal Decomposition

N,N-bis(2-hydroxybenzyl)alkylamines, benzoxazine dimers, are the major product produced from benzoxazine monomers on mono-functional phenol by the one step ring opening reaction. Due to the metal responsive property of benzoxazine dimers, in this present work, N,N-bis(5-methyl-2-hydroxybenzyl)methylamine (MMD), N,N-bis (5-ethyl-2-hydroxybenzyl)methylamine (EMD), and N,N-bis(5-methoxy-2-hydroxybenzyl) methyl amine (MeMD), are considered as novel ligands for rare earth metal ion, such as cerium(III) ion. The complex formed when the clear and colorless solutions of cerium nitrate and benzoxazine dimers were mixed, results in a brown colored solution. The metal-ligand ratios determined by the molar ratio and the Job's methods were found to be in a ratio of 1:6. To clarify the evidence of the complex formation mechanism, the interactions among protons in benzoxazine dimers both prior to and after the formation of complexes were determined by means of (1)H-NMR, 2D-NMR and a computational simulation. The single phase ceria (CeO(2)) was successfully prepared by thermal decomposition of the Ce(III)-benzoxazine dimer complexes at 600 °C for 2 h, was then characterized using XRD. In addition, the ceria powder investigated by TEM is spherical with an average diameter of 20 nm.     

Electrolyte materials for solid oxide fuel cells derived from metal complexes: Gadolinia-doped ceria

Gadolinia doped ceria (GDC) powders with different gadolinium contents were successfully prepared by the thermal decomposition of ceria complexes. All the calcined powder samples were found to be ceria-based solid-solutions having a fluorite-type structure. The powders were cold-isostatically pressed and sintered in air at 1500 °C for 5 h to attain a sintered density of about 90% of its theoretical value. The electrical conductivity of the GDC pellets in air was studied as a function of temperature in the 225–700 °C range, by using two-probe electrochemical impedance spectroscopy measurements. The highest total conductivity (σ_600 °C = 0.025 S/cm) was found for the Ce_0.85Gd_0.15O_1.925 composition.     

Development of novel hybrid materials from polylactic acid and nano-silver coated carbon black with distinct antimicrobial and electrical properties

This work aims to prepare nanosilver coated carbon black via benzoxazine oxidation as a filler for polylactic acid (PLA) to produce novel hybrid materials with improved electrical and antimicrobial properties. Nanosilver coated carbon black exhibited antimicrobial activity against S.aureus, B.subtilis, M.luteus, E.coli, P.aeruginosa and C.albicans. It was found that the nanosilver coated carbon black (10CB-Ag) was the most effective filler since it showed largest inhibition zones. Thermogravimetric analysis (TGA) showed that the silver content in 10CB-Ag was 5.68% by weight. The hybrid materials of PLA with uncoated carbon black and nanosilver coated carbon black fillers were prepared by injection molding. The optimal composition of the prepared hybrid materials was found to be 15 phr of nanosilver coated carbon black in PLA (15AgCB-PLA). This material showed quite good properties, e.g. tensile strength of 50 MPa, % elongation at break of 1.68 and electrical conductivity of 2.78 × 10^?9 S?m^?1. Moreover, it exhibited the S. aureus inhibition of about 99%. This work revealed the possibility of using this material for anti-electrostatic and antimicrobial applications.