Capillary Flow of Cationic Polyelectrolyte Solutions

The flow rates and the dynamic contact angles of aqueous solutions of cationic polyelectrolyte (CPE) in quartz capillaries with radius of 3–4 m are measured. It is shown that the surface tension and viscosity of CPE solutions with concentrations from 10^–1 to 10^–5 g/l are the same as for water. Surface inactivity of CPE leads to the substantial difference between the capillary properties of their solutions and those of surfactant solutions. It is established that, as the solution concentration increases, the advancing contact angles are reduced from 83° to 75°; the receding contact angles lie between 10° and 20°. Large hysteresis of contact angle can probably be related to the formation of metastable wetting film behind the receding meniscus. Surface hydrophobization occurs as a result of the adsorption of CPE molecules on the negatively charged quartz surface. The specific features of the application of CPE solutions in the deposition technology of hydrophobic coatings, the capillary imbibition and displacement of oils from hydrophobic pores are discussed.     

Kinetics of Gas Bubble Motion in a Capillary

Two flow regimes were discovered by measuring flow rate vof water through thin capillaries containing small gas bubble. The first regime is realized at a low pressure drop P, when the main resistance to flow is created by the wetting film. The estimate of its thickness makes it possible to determine the parameters of the isotherm of the electrostatic component of the disjoining pressure corresponding to the constant charge of the film–gas interface and potential of the quartz surface, which requires the application of a new calculation procedure. As Pincreases, an advancing meniscus forms contact angle of 50°–60° due to the film rupture when it reaches critical pressure in the thinnest part near the meniscus. In this case, the rate vis controlled by the flow in the filled part of a capillary, although some additional viscous drag is also created by the film moving in front of advancing meniscus. The longer the bubble, the greater this contribution.     

Synthesis of dodeca-8e, 10e-dien-1-ol — the sex pheromone ofLaspeyresia pomonella via the acetolysis of 4-propenyl-1,3-dioxane

A new scheme has been developed for the synthesis of dodeca-8E,10E-dien-1-ol (the sex pheromone of the codling moth) from sorbyl acetate, available from 4-propenyl-1,3-dioxane through the intermediate diacetate of 3 propenyl-2-oxapentane-1, 5-diol.Scientific Research Institite of Fine Organic Synthesis, Academy of Sciences of the Republic of Bashkortostan, Ufa. Institute of Organic Chemistry of the Scientific Center, Russian Academy of Sciences, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp 602–604, July–August, 1996. Original article submitted January 29, 1996.     

Manifestation of a synergistic effect in technological heredity

The differential effect of technological heredity on the characteristics of adhesives and operating properties of adhesive joints has been considered on the basis of the main technological operations of the bonding process. Based on an expert assessment of the main characteristics of the adhesive material (with the exception of fracture shear stress and ultimate tensile strain), it has been found that technological operations of the bonding process have no effect on technological heredity. This conclusion is controversial; to take into account this effect, we suggest using the synergistic effect.     

Synthesis of Ethyl (2E)-5-Phenylpent-2-en-4-ynoate

Russian Journal of Organic Chemistry - An efficient procedure has been developed for the synthesis of ethyl (2E)-5-phenylpent-2-en-4-ynoate by olefination-dehydrohalogenation of...     

Features of Research on the Thermophysical Properties of Road-Building Materials

In this article, the main stages of planning and conducting an experiment in the study of thermophysical properties of road-building materials are considered. The results of experimental studies of asphalt–concrete mixtures are presented. A technique for statistical analysis of experimental data is described.     

Current prepreg-formation technologies

Formation technologies for prepregs intended for items made of glass and carbon fiber are discussed. A comparison of prepreg technologies that are used for manufacturing thermoplastic and thermoreactive binders is given. Advantages of standard prepreg-formation technologies (solution and melt type) and modern sheet molding compounds and bulk molding compounds) are considered.