Adsorptionsmodifizierung der oberfläche von mineralischen polymerfüllstoffen als die methode deren aktivierung

The process of modifying the surface of particles of dispersed polymer fillers, using tensides, has been studied. The main principles were established with regard to the effect of modification of titanium dioxide and kaolin on the structure formation in solutions and block formations of chlorinated poly(vinyl chloride) resin and rubber, depending on the nature and concentration of the modifier. The decisive part played by chemisorption of the tenside in lyophilization (water-repellency treatment) of the surface of the filler and its activation, as a structure former, has been elucidated.     

Composition of lipids of the grain of opaque-2 maize

It has been established that the change in the composition of the total lipids and the fall in the fatty acid content depend on the initial maize genotype. A decrease in the amount of unsaponifiable substances in the grain of mutants is accompanied by qualitative changes in the composition regardless of the nature of the genotype.Scientific-Research Institute of Biology Dnepropetrovsk State university. Translated from Khimiya Prirodnykh Soedinenii. No. 3. pp. 360–363. May–June, 1988.     

Inter-ring rotational potential of biphenyl and its effect on poly(p-phenylene)

Detailed ab initio studies have been done on the inter-ring torsional states of the biphenyl molecule using self-consistent field molecular orbital method. The potential goes through a minimum at an angle of 38°. The height of the potential barrier for the coplanar state is 2.01 kcal/mol. When the phenyl rings are perpendicular to each other, this height increases to 2.37 kcal/mol. The role of correlation and polarization is found to be important. The shape of the potential suggests that polyparaphenylene may possibly exist as a super helix.     

Cyclization of n-alkylazinium cations with bisnucleophiles. 4. Regio- and stereospecificity of the reactions of β-diketones with quinoxalinium salts and their aza and benzo analogs

The reactions of substituted quinoxalinium, benzo[g]- and benzo[f]quinoxalinium, and pyrido[2,3-b]pyrazinium salts with anions of -dicarbonyl compounds give furo[2,3-b]-annelated systems with strictly determined regio- and stereoorientations.See [1] for Communication 3.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1543–1548, November, 1981.     

Mesoionic 1-amino-1,3,4-triazole-2-thiones and their azomethine derivatives

The reaction of triethylammonium salts of -acyldithiocarbazic acids with sodium chloroacetate and hydrazine leads to the formation of mesoionic 1-amino-1,3,4-triazole-2-thiones, which react with aldehydes to give the corresponding azomethine derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 424–428, March, 1976.     

Steric structure of phosphorus-contaiming heterocycles

Conclusions The steric structure of 3-halo-1-thia-3-phosphethanes with a tetracoordinated phosphorus atom was investigated by the methods of dipole moments and Kerr constants, enlisting data on quantum chemical calculations of the energies of the conformations.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2240–2244, October, 1973.The authors would like to thank I. M. Shermergorn for providing the samples for the investigations.     

Friedel-crafts copolymerization of thiophene and p-di(chloromethyl)benzene. II. Products of the later stages of the reaction

Products of the copolymerization of thiophene and p-di(coloromethyl)benzene in presence of stannic chloride have been separated by using gel-permeation chromatography (GPC) and identified by using principally mass, infrared, and nuclear magnetic resonance spectroscopy. The GPC separation is not nearly as efficient as the separation of the products of the corresponding benzene–DCMB and diphenylmethane–DCMB reactions which have previously been described. A further complication which makes a kinetic analysis of this reaction more difficult is the occurrence of intramolecular condensation of certain of the earlier products leading to cyclic structures incorporating four aromatic rings. These investigations have made it possible to deduce some of the principal structural differences between the thiophene–DCMB and benzene–DCMB polymers which may have some bearing on the differences which have been found in their thermal stabilities.     

EDXRF as an analytical tool in art: Case studies from pigment identification and treatment assessment

Energy dispersive X-ray fluorescence (EDXRF) was employed for the identification of pigments decorating Hellenistic figurines, and the assessment of the efficiency of a treatment with barium hydroxide applied to stone. Elements present in the colored areas of the figurines, as well as the treated stone was identified by EDXRF. These data together with complementary information obtained by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analysis (XRD) led to the identification of several precious pigments. As far as the treatment efficiency is concerned, EDXRF analysis revealed that barium is unevenly distributed on the treated surface and reaches a maximum depth of 2.5 mm.