Surface‐active metal‐coordinated oligoperoxidic radical initiators. I. The interrelation between the microstructure of ditertiary oligoperoxides and their ability to form stable metal complexes

Carbon‐chain heterofunctional oligoperoxides (HFOs) with ditertiary peroxidic, carboxy, or hydroxy groups formed stable coordinated complexes through their interaction with transition‐metal salts in organic solutions. The oligomeric metal complexes (OMCs) were separated from the reaction mixture and investigated through elemental analysis, voltammetry, and atom‐adsorption, IR, and UV spectroscopy. From these investigations and the calculated values of the mole fraction and formation constants of the stable complexes of the copper cations and HFOs, the probable cooperative mechanism of the complex formation by such oligomers was suggested. The existence of two levels of HFO molecule ordering, namely HFO microstructure and the structure of the hydrogen‐bonded complexes formed by HFOs, explained the cooperative mechanism and some characteristics of the OMC formation. The mole fraction and formation constants of the OMCs were interrelated with the disposition of the complex‐forming groups in the chain of HFOs. From the experimental data, it can be concluded that the complex‐forming groups of the HFOs possessed different reactivities both in the complex formation with metal cations and in the reactions involving the resulting OMCs. The shift in the half‐wave potential of the  O:O bond reduction during the transition from the HFO to a mixture of HFO and Cu²⁺ and to OMC indicated an increase in its reactivity. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 516–527, 2000     

An effect of low temperature processing on stability of physical and chemical properties of amorphous alloy Fe78.5Ni1.0Mo0.5Si6.0B14.0

As a result of detailed investigation of physico-chemical properties of the amorphous alloy ribbon Fe_78.5Ni_1.0Mo_0.5Si_6.0B_14.0 it was found that its high-speed cooling (1–3 s) with a temperature gradient ΔT = (298–77) K affects chemical reactivity of surface at constant volume parameters: microhardness, magnetic properties. This feature can be used for special applications of metal-doped amorphous alloy based on Fe in extreme conditions.     

Catalytically active electrodes in the redox processes of oligomeric peroxides

The catalytic activity of different electrodes (Pt, glassy carbon, and amorphous metal alloys Al_87.0Y_5.0Ni_8.0, Fe_78.5Ni_1.0Mo_0.5Si_6.0B_14.0, and Fe_73.1Cu_1.0Nb_3.0Si_15.5B_7.4) in the redox processes of polyfunctional oligomeric peroxides based on vinylacetate, 3-tert-butylperoxy-3-phenylbutylmethylmethacrylate and maleic anhydride and vinylacetate, 3-tert-butylperoxy-3-methylbutylmethacrylate and maleic anhydride was evaluated by potentiometry and cyclic voltammetry. It was established that amorphous metal iron-based Fe_73.1Cu_1.0Nb_3.0Si_15.5B_7.4 and Fe_78.5Ni_1.0Mo_0.5Si_6.0B_14.0 electrodes manifested a high electrocatalytic activity comparable with that of a platinum electrode in the redox processes of polyfunctional oligomeric peroxides.     

Nanocrystallization and structure of Fe78.5Ni1.0Mo0.5Si6.0B14.0 amorphous alloy

The effect of Ni and Mo alloying additions on crystallization of an Fe–Si–B based amorphous alloy was studied by applying various experimental techniques – DSC, XRD and TEM. It was shown that both alloying additions Ni and Mo change the crystallization temperature as well as the activation energy of primary crystallization. The phases formed during primary crystallization for the Fe₈₀Si₆B₁₄ and Fe_78.5Ni₁Mo_0.5Si₆B₁₄ alloys were the same, however the morphologies were significantly different. The addition of 1.0 at.% of Ni and 0.5 at.% Mo changed the crystallization mechanism and the type of formed phases. Such additions also resulted in formation of nanocrystals. The kinetic and thermodynamic characteristics of annealed specimens of amorphous metallic Fe₈₀Si₆B₁₄ and Fe_78.5Ni₁Mo_0.5Si₆B₁₄ alloys were established. These characteristics were determined based on measurements of instantaneous changes of electrical strength. It was shown that the method of electromotive force measurements was more sensitive to structural changes and the phase composition of amorphous metallic electrodes in comparison with the X-ray method.     

Thermal Stability and Polarographic Reduction of Peroxy Esters of o(m)-Carborane-1-carboxylic and Benzoic Acids

The thermal stability of some peroxy esters of o(m)-carborane-1-carboxylic and benzoic acids (taken for comparison) was evaluated by thermal analysis. The polarographic reduction of these compounds on a mercury dropping electrode was studied. The parameters of the electrochemical reduction and thermal decomposition of the peroxy esters were analyzed.     

Influence of structurization of amorphous metallic alloys Al87Y5 − x Gd x Ni8 − y (x = 0, 1, 5; y = 0, 4) on their mechanical properties

Amorphous metallic alloys (AMAs) Al₈₇Y₅Ni₈, Al₈₇Gd₅Ni₈, Al₈₇Y₄Gd₁Ni₈, Al₈₇Y₄Gd1Ni₄Fe₄, and Al₈₇Gd₅Ni₄Fe₄ produced by melt spinning on a cooled substrate have been studied. Based on the data of differential scanning calorimetry and X-ray diffraction, the activation energies of individual stages of crystal-lization, the sizes and volume fractions of nanocrystals in an amorphous matrix have been calculated. The alloying of AMAs with Y or Gd is shown to lead to the formation of particles with sizes of 9–15 nm at the first stage of nanocrystallization, which provides their high microhardness.     

Low‐temperature surface‐active complex‐radical oligodert.Alkylperoxidic initiators

Carbon‐chain functional surface‐active oligoperoxides (FSAP) with ditertiary peroxidic, carboxyl or hydroxyl groups form stable oligoperoxidic metal complexes (OMC) through their interaction with transition metal salts in organic solutions. The mole fraction and formation constants of OMC are interrelated with the microstructures of FSAP, first of all, with the disposition of complex forming groups. Increasing the set of FSAP conformational structures promotes the enhancement of the local concentrations of reactants in the reaction zone during complex formation, thereby increasing the probability that the reaction will proceed. The kinetic and thermodynamic characteristics of the decomposition of peroxide fragments of FSAP in the aqueous medium providing the formation of controlled amount of free radicals, thereby the initiation of emulsion polymerization processes were investigated. The realization of the process of decomposition of – O:O – bonds as a result of homolytic dissociation or/and Red‐Ox reactions depending media polarity and OMC nature were assumed.