Synergistic effect of supported nickel catalyst with intumescent flame-retardants on flame retardancy and thermal stability of polypropylene

Supported nickel catalyst (Ni-Cat) was used as a catalyst to improve the flame retarclancy of intumescent flame-retardants (IFR) systems based on ammonium polyphosphate and pentaerythritol (PETOL) in polypropylene (PP) matrix. Limited oxygen index (LOI), UL-94 rating, and thermogravimetric analysis were used to characterize the flame retardancy and thermal stability of the PP systems, and field emission scanning electron microscopy (FE-SEM) and Fourier transformed infrared spectroscopy (FTIR) were used to analyze the microstructure and composition of the chars formed during measuring LOI value and after combustion at 800 degrees C. The catalytic effect of NiCat was shown in an increase of LOI, a change in the char microstructure, and improvement of the thermal stability in the PP systems, which result from the synergistic effect of Ni-Cat and IFR. The results from FE-SEM and FTIR spectra of the char can explain how this synergistic effect happened.

Synthesis, characterization, crystal structure and magnetic property of asymmetrical double Schiff base heterotrinuclear complex: Cu(II)-Co(II)-Cu(II)

An asymmetrical double Schiff-base Cu(II) mononuclear complex, HCuLp (H(3)Lp is N-3-carboxylsalicylidene-N'-5-chlorosalicylaldehyde-1,3-diaminopropane) and a heterometal trinuclear complex with double molecular structure (CuLp)(2)Co center dot 5H(2)O have been synthesized and characterized by means of elemental analyses, IR and electronic spectra. The crystal structure of the heterotrinucler complex was determined by X-ray analysis. Each asymmetric unit within the unit cell of the complex contains two heterotrinuclear neutral molecules (a) [CuLpCoCuLp], (b) [(CuLpH(2)O) CoCuLp] and four uncoordinated water molecules. In the two neutral molecules, the central Co2+ ions are located at the site of O-6 with a distorted octahedral geometry, one terminal Cu2+ ion (Cu(3)) at the square-pyramidal environment of N2O3, and the other three at the square planar coordination geometry with N2O2 donor atoms. Magnetic properties of the heterotrinucler complex have been determined in the temperature range 5-300 K, indicating that the interaction between the central Co2+ ion and the outer Co2+ ions is antiferromagnetic.

A novel 2D arsenic vanadate network grafted with a transition metal complex: [Cu(phen)][(VV4As2O19)-V-IV-As-V]center dot 0.5H(2)O

A novel organic-inorganic hybrid compound [Cu(phen)](2)[(VV4As2O19)-V-IV-As-V-O-V].0.5H(2)O 1 has been hydrothermally synthesized. Its structure, determined by single crystal X-ray diffraction, exhibits an unusual two-dimensional arsenic vanadate layered network grafted with the [Cu(phen)](2+) complex. The chelating phen ligands project perpendicularly beyond the inorganic layer. Variable temperature magnetic susceptibility studies indicate that both ferro- and antiferro-magnetic interactions exist in 1.

Synthesis, crystal structure, and magnetic properties of {[Cu(oxbe)]Mn(H2O)[Cu(oxbe)(DMF)]}(n)center dot nDMF center dot nH(2)O: From dissymmetrical mononuclear entities to a 3D heterometallic supramolecular coordination polymer

Self-assembly of the building block [Cu(oxbe)](-) with Mn(II) led to a novel coordination polymer {[Cu(oxbe)]Mn(H2O)(Cu(oxbe)(DMF)]}(n).nDMF.nH(2)O, where H(3)oxbe is a new dissymmetrical ligand N-benzoato-N'-(2-aminoethyl)-oxamido and DMF = dimethylformamide. The crystal forms in the triclinic system, space group P(1)over-bar, with a = 9.260(4) angstorm, b = 12.833(5) angstrom, c = 15.274(6) angstrom , alpha = 76.18(3)degrees, beta = 82.7(3)degrees, gamma = 82.31(3)degrees, and Z = 2. The crystal structure of the title complex reveals that the two-dimensional bimetallic layers are constructed of (CuMnII)-Mn-II-Cu-II chains linked together by carboxylate bridge and hydrogen bonds help to produce a novel three-dimensional channel-like structure. The magnetic susceptibility measurements (5-300 K) were analyzed by means of the Hamiltonian (H)over-cap = -2J(S)over-cap (Mn)((S)over-cap(Cu1) + (S)over-cap(Cu2)), leading to J = -17.4 cm(-1).