The structure and properties of drawn blends of polyethylene and polypropylene

A series of highly oriented tapes has been prepared from a blend consisting of equal proportions of polyethylene and polypropylene. The mechanical properties and the structure and morphology of the samples have been investigated using DSC, optical microscopy, and wide angle and small angle diffraction, including measurements of crystal strain on samples under stress. It has been confirmed that the blend is incompatible, and a structural model has been proposed which is consistent with the observation that the polyethylene and polypropylene components act essentially independently in their response to external macroscopic stress.     

Sintering of Glass

It has been shown by a simple experiment on the closing of capillary glass tubes on heating that the final stage of sintering of glass particles, manifesting itself in densification of the compact, proceeds by viscous flow caused by surface tension. This effect has been predicted theoretically by Frenkel.     

Reaction of sintered spinel and corundum refractories with some compounds

Conclusions We investigated the reaction of sintered spinel, spinel-corundum, and corundum refractories with certain oxides at 1500–1750°C. We established conditions in which refractories are stable in respect to the action of individual oxides. We also investigated the mineral compositions of the reaction zones.The least reaction with all the oxides investigated occurs in the spinel refractory, and the greatest in the corundum; that is, there is an increase with rise in alumina content. Magnesia spinel hardly reacts with iron oxides in the test conditions.Magnesia spinel is very resistant to sodium adipates which extensively damage sintered corundum.Carbonates of alkali and alkaline-earth elements, and also fused alkalis at temperatures exceeding their melting points by 200°C seriously damage spinel-corundum refractories, but do not react with sintered corundum or spinel.Metallic fluorides damage corundum but do not react with spinel and spinel-corundum sintered refractories.Thus, spinel sintered refractory should find extensive use in conditions of corrosive action, in particular, alkalis and oxides of iron.Translated from Ogneupory, No. 1, pp. 37–42, January, 1968.     

Forms of extraction of silicon compounds in rice husks

The forms of extraction of silicon compounds in rice husk, proposed as a source of silicon dioxide, were examined. A model in which the silica particles distributed in the plant cells of rice husk are separated by organic layers from mineralizer impurities was proposed. Crystallization of silicon dioxide begins after elimination of the layers of carbon formed at the site.     

Metal recovery in a pilot-scale rotating cylindrical wiper-blade electrode system

The performance of an experimental pilot-scale electrochemical reactor using a rotating cylindrical electrode equipped with wiper blades is described. Data obtained from monopolar depositing and bipolar stripping—depositing of copper from dilute aqueous electrolytes are presented and certain economic aspects of metal recovery are discussed.     

Effects of soaking soybeans in dilute acids on biologically active components

Soaking soybeans in dilute acids affected activities of lipoxygenase, trypsin inhibitor and urease. Effects of soaking time, acid concentration and soaking temperature were investigated. Lipoxygenase activity was completely eliminated by soaking in 0.3 M HC1 at either 23°C or 40°C for 8 hr. Less than 50% trypsin inhibitor remained and urease was inactivated to an acceptable level (0.04 ΔpH).     

Configurational statistics of copolymers prepared by complex-radical polymerization

Radical copolymerization is considered theoretically taking into account the effect of complexing on the configurational statistics of macromolecules formed. Akinetic model has been developed that considers, apart from the ordinary addition of single monomer units to a propagating chain, the possible addition of monomer unit pairs along with a complexing agent in the form of a ternary complex. Within the framework of this model, the problem of calculating the probabilities of formation of any sequences of monomer units (taking into account their microtacticity) in a macromolecule has been rigorously solved as well as the problem of finding the composition distribution of the copolymer formed. It has been shown that this distribution is described by a conventional Gauss law and the appropriate parameters are given. Possible generalizations of the suggested approach are indicated.     

Hydrocracking of n-heptane. Study of NiO—MoO3 catalysts supported on a HY ultrastable zeolite

The hydrocracking of n-heptane in the temperature range of 573 to 623 K and at 2.45 × 10⁶ Pa pressure has been employed as a test reaction for the study of Ni—Mo bifunctional catalysts supported on a HY ultrastable zeolite. Two groups of catalysts containing 8 and 12 wt% of MoO₃ and different amounts of NiO have been studied. In both series a maximum in the activity has been obtained for catalysts with a Ni/Mo atomic ratio of 0.8-1.0. The order of the impregnation of the oxides can have little influence on the activity. The most active catalyst has been obtained when the zeolite is exchanged with NH⁺₄ ions until the Na⁺ level is less than 2% of the original and calcined at 823 K to obtain a HY ultrastable zeolite. Using this catalyst the rate controlling step could be the transformation of the carbonium ion on the acid sites.