Oxo-fluoro-aluminates and -gallates

The preparations of (NH₄)₂HAl₂OF₇, (NH₄)H₂AlOF₄, (NH₄)₂HGa₂OF_7^·3.5H₂O and (NH₄)₂HGaOF₄ are described. IR spectra suggest the presence of MOMO chains in these compounds. On isothermal heating at 180°C (NH₄)H₂AlOF₄ decomposes to give (NH₄)HAlOF₃, and at 150°C (NH₄)₂HGaOF₄ yields (NH₄)H₂GaOF₄. At 18°C (NH₄)₂HGa₂OF_7^·3.5H₂O yields the anhydrous compound.     

Spectrophotometric determination of europium in aqueous samples and interference of Fe3+, UO22+ and Th4+ and other complexing agents on determination

Journal of Radioanalytical and Nuclear Chemistry - Due to the high neutron absorption cross section, Eu is having stringent specification limits in U, Pu and Th based nuclear fuel materials....     

Three‐Dimensional Structure of Olefinic Thermoplastic Elastomer Blends Using Electron Tomography

Summary: The present communication reports the first use of electron tomography in reconstructing the three‐dimensional morphology in thermoplastic elastomer blends. The blends investigated were dynamically vulcanized blends of ethylene‐propylene‐diene (EPDM) rubber/poly(propylene)/oil and polystyrene‐block‐(ethylene‐co‐butylene)‐block‐polystyrene (SEBS)/poly(propylene)/oil. An easy identification of blend morphology could be carried out at blend compositions, where conventional transmission electron microscopic imaging gives misleading information. This technique gives a higher resolution than any other microscopic technique, and is applicable to blends with dispersed as well as co‐continuous morphologies.

Example of a tomographic model of partially co‐continuous SEBS phases in a SEBS/PP/oil thermoplastic blend. Only the contours of the SEBS phase are shown.     

Electron beam irradiated polyamide-6,6 films—II: mechanical and dynamic mechanical properties and water absorption behavior

Electron beam irradiation of poly(iminohexamethylene-iminoadipoyl) (Polyamide-6,6) films was carried out over a range of irradiation doses (20–500 kGy) in air. The mechanical properties were studied and the optimum radiation dose was 200 kGy, where the ultimate tensile stress (UTS), 10% modulus, elongation at break (EB) and toughness showed significant improvement over the unirradiated film. At a dose of 200 kGy, the UTS was improved by 19%, the 10% modulus by 9% and the EB by 200% over the control. The dynamic mechanical properties of the films were studied in the temperature region 303–473 K to observe the changes in the glass transition temperature (T_g) and loss tangent (tan δ) with radiation dose. The storage modulus of the film receiving a radiation dose of 200 kGy was higher than the unirradiated film. The water uptake characteristics of the Polyamide-6,6 films were investigated. The water uptake was less for the films that received a radiation dose of 200 and 500 kGy than the unirradiated film. The role of crystallinity, crosslinking and chain scission in affecting the tensile, dynamic mechanical and water absorption properties was discussed.     

Mechanical properties of oriented fibres of semicrystalline polymers based upon orientation function from optical properties

The computation of the orientational averages is a great problem in the case of semicrystalline polymers. In a previous communication [1] it has been shown that sin=f() sin describes the orientational changes satisfactorily for a certain class of polymers. In this paper some alternative deformation schemes are also discussed. It has been concluded that birefringence provides a useful guideline in the choice of a deformation scheme.     

Thermal studies on titanyl,zirconyl and hafnyl dithiocarbamato complexes

The dithiocarbamato complexes of titanyl(IV), zirconyl(IV) and hafnyl(IV), abbreviated as MO(S₂CNRR)₂·nH₂O(M=Ti, Zr or Hf,R=H,R=C₅H₉;R=H,R=C₇H₁₁,n=1 for Ti andn=2 for Zr and Hf), were prepared in aqueous medium and characterized by elemental analyses, magnetic susceptibility measurements and IR spectral studies. The thermal behaviour of these compounds under non-isothermal conditions was investigated by thermogravimetric, derivative thermogravimetric and differential scanning calorimctric techniques in nitrogen and oxygen atmospheres. The intermediates obtained at the end of various thermal decomposition steps were identified on the basis of analyses and IR spectral studies. Kinetic parameters, such as apparent activation energy and order of reaction, were determined by the graphical method of Coats and Redfern. The heats of reaction for the different decomposition steps were calculated from the DSC curves.

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Zusammenfassung Die Thiocarbamato-Komplexe von Titanyl(IV), Zirkonyl(IV) und Hafnyl(IV) der allgemeinen Formel MO(S₂CNRR)₂·n H₂O (M=Ti, Zr oder Hf;R=H, R=C₅H₉;R=H, R=C₇H₁₁;n=1 für Ti undn=2 für Zr und Hf) wurden in wässrigem Medium hergestellt und durch Elementaranalyse, Messung der magnetischen Suszeptibilität und IR-Spektraluntersuchungen charakterisiert. Das thermische Verhalten dieser Verbindungen unter nicht-isothermen Bedingungen wurde durch TG, DTG und DSC in Stickstoff- und Sauerstoffatmosphäre untersucht. Die nach verschiedenen thermischen Zersetzungsschritten erhaltenen Zwischenprodukte wurden durch chemische Analyse und IR-Spektroskopie identifiziert. Kinetische Parameter, wie die scheinbare Aktivierungsenergie und die Reaktionsordnung, wurden nach der graphischen Methode von Coats und Redfern bestimmt. Für die einzelnen Zersetzungsschritte wurden die Reaktionswärmen aus den DSC-Kurven berechnet.

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, . MO(S₂CNRR)₂·nH₂O (M=I, Zr, Hf,R=H,R ¹=C₅H₉, C₇H₁₁,n=1 I =2 ) , . , . , , . - . .

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The authors are grateful to Dr. Shyam Kumar for helpful discussions.