Photooxidative behaviour of polyethylene/polyamide-6 blends

The photochemical behaviour of several polyethylene/polyamide-6 blends was studied under conditions of artificial accelerated weathering. Particular attention was paid to five different compositions ranging from pure polyethylene to pure polyamide with blends of PE/PA-6 of various compositions: 75/25, 50/50 and 25/75 wt/wt%. Analysis by infrared spectroscopy of the chemical modifications caused by photooxidation showed that exposing the polyethylene/polyamide-6 blends to UV-light irradiation led to the formation of oxidation photoproducts in both polymer phases. In agreement with both the mechanical and spectroscopic analyses, the photooxidation rate of the blends was observed to be much higher than that of the homopolymers. The results given in this paper suggest that photooxidation of the PE/PA blends starts in the polyamide phase and that the subsequent photooxidation of the polyethylene phase may be initiated by the radicals coming from the oxidation of PA.     

1-Substituted quinolin-4-one imines with biological activity. I

Conclusions The interrelationship between structure and pharmacological activity has been studied in a series of 1-substituted quinolin-4-one imines. It has been shown that some derivatives may be of interest for medicinal use.Khimiya Prirodnykh Soedinenii, Vol. 6, No. 1, pp. 98–101, 1970     

Characterization of a thin CeO2-ZrO2-Y2O3 films electrochemical deposited on stainless steel

In this paper, we report for the first time formation of a thin CeO₂-ZrO₂-Y₂O₃ films electrodeposited on a stainless steel substrate. The samples have been characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The XRD and XPS data indicate formation of a solid solution and additional existence of Ce³⁺ states near the surface. After annealing, SEM examination has shown a microstructure formed by dispersed spherical agglomerates having a size between 20 and 60 nm.     

Chemical healing in partially cross-linked polyamides

Evidence is presented for chemical healing—healing resulting from chemical reactions between neighboring macromolecules located at the interface surface—which has recently been reported in linear polycondensates. In order to distinguish the contribution of the solid-state reaction from the healing effect, samples (nylon-11, nylon-12, and nylon-6,6) with strongly restricted chain mobility (by crystallization and chemical cross-linking in the amorphous zones) have been used. It has been found that under the same healing conditions the cross-linked samples display better welding than the un-cross-linked ones. The conclusion is drawn that the observed healing effect is due mainly to the solid-state chemical reactions at the contact surfaces and not to the diffusion of macromolecules. The results obtained can be considered as an indication of the existence of “chemically released diffusion” in the solid state, i.e., motion of chain segments owing to the interchain and/or intrachain chemical reactions, mainly of the exchange type.     

Comparative characteristics of the ion-exchange properties of natural clinoptilolites from Bulgaria and the USSR for the purpose of purification of liquid wastes from nuclear power plants. Part I: Study of the equilibrium sorption of cesium and strontium ions from solutions of different composition

The ion-exchange equilibrium of cesium and strontium ions on clinoptilolites from different deposits — Dzegvi and Tedzami /Georgian SSR/, Beli Plast and Beli Bair /Bulgaria/ in different cationic forms of the sorbents /natural, sodium, calcium and ammonium/ is studied. The static ion-exchange capacities are determined. The sorption isotherms are plotted and the corresponding distribution coefficients are calculated. Mechanical characteristics which are important for the assessment of the technological use of the sorbents in dynamic conditions are determined. The clinoptilolite from Beli Plast deposit has the highest capacity in comparison with the other studied zeolites. The selectivity of the clinoptilolites from Bulgarian deposits is independent of the cationic form of the sorbent while the selectivity of the Georgian clinoptilolites strongly depends on the cationic form; the selectivity of the ammonium form of Tedzami sorbent is the highest.