Investigation of rheological properties of graphene oxide and its nanocomposite with polyvinyl alcohol

Abstract. This paper focuses on the rheological properties of graphene oxide (GO) and its nanocomposite with polyvinyl alcohol (PVA). The purpose of this paper is to compare the mechanical properties of these materials. GO is a nanomaterial that has been widely studied in engineering. The comparison of its rheological properties with those of its nanocomposite with PVA has been required. Rheology is an appropriate method for the comparative investigation of the mechancial behavior of these materials.

Development of Strengthened Bioactive Calcium Phosphate-Silicate Glass Ceramics for Bone Implants

Cumulative experience in the field of development of bioactive glass ceramics for bone implants and methods of strengthening thereof have been analyzed. Compositions were selected and model glasses were synthesized, the relationship between viscosity and crystallization ability of glass ceramics has been studied. Composite materials based on the glass ceramics and zirconia have been synthesized, their mechanical properties studied, and feasibility of their use in the creation of bone implants has been established.

Rheological Properties of Polymer Colloid–Cellulose Thickener Systems

An approach to water emulsions modification with structure forming additives, namely cellulose esters, is proposed in the article. Influence of the film former origin on the system rheological properties at different shear-strain rates was examined. Structural and mechanical, as well as rheological properties of the studied systems were determined. The results confirm that hydroxyethylcellulose has a greater structure forming effect in comparison with carboxymethylcellulose.

Biocompatible Gel-like Forms of Drugs on the Basis of Solutions of Polysaccharide Chitosan with Alcohols

We propose an approach to the preparation of viscoelastic systems based on chitosan without crosslinking agents. It is the formation of an additional network of physical links by introducing a low molecular weight modifier – ethanol or glycerol. It turns out that gelation of chitosan in the solution is accompanied by the formation of additional meshes of physical links, nodes or aggregates of chitosan macromolecules formed in a mixed solvent of acetic acid-water-glycerol or acetic acid-waterethanol.

Вплив електролітів на реологічні властивості шлікерів із глин різного мінералогічного складу

The experimental researches of regulation of rheology properties of clay mixture by using to clays the additives of mineral and organiccontained electrolytes in ceramics technology are given.  Подано експериментальні дослідження регулювання реологічних властивостей шлікерів за допомогою використання до глин добавок мінеральних і органовмісних електролітів у технології кераміки.

The effect of zeolite addition at a temperature compaction of asphalt mixes

The beginnings of warm mix asphalt are connected with the use of foamed asphalt in the ‘60s of the last century. Asphalt foaming occurs by contact with water or water steam that can be entered mechanically or under pressure. The foaming effect can be also obtained by the adding of zeolite to the asphalt mixture which causes the lower viscosity of the asphalt, better workability and adhesiveness of the mixture to the aggregate in lower temperatures. Presently, synthetic zeolites Aspha-Min and Advera are used for reducing the processing temperature.

Дослідження в’язкості золь-гель систем на основі тетраетоксисилану

The sol-gel systems of tetraethoxysilane (TEOS) – solvent – water systems at gelation viscosity dynamics has been investigated by means of viscosimetry. The influence of different factors (temperature, concentration of initial substances and the sol-gel process initiator) on the gelation rate has been established. The measurement of viscosity gradient dependence allowed to determine an elastic and friction components of viscosity using optimization method in the ORIGIN 5.0. program.

Фізико-хімічні закономірності модифікування ненасичених поліестерів полівінілхлоридом

Досліджено фізико-хімічні закономірності модифікування ненасичених поліес-
терних смол полівінілхлоридом у присутності діестерфталатних пластифікаторів.
Встановлено вплив компонентного складу на особливості морфологічних змін та
характер міжмолекулярних взаємодій у модифікованих поліестерних композиціях.
Досліджено вплив полівінілхлориду і дибутилфталату на кінетику зміни в’язкості
модифікованих поліестерних композицій. Виявлено, що характер термомеханічних
кривих значною мірою залежить від компонентного складу модифікованих поліес-

The influence of the solveny medium on the aggregation of asphaltene macromolecules and determination of their molar mass

The formation of aggregates of a fraction of asphaltenes extracted from Brazilian crude oil was investigated by measuring the interfacial tension and kinematic viscosity of their solutions prepared in different solvents. The interfacial tension results indicate the existence of critical micelle concentration (CMC) levels of the asphaltenes in solvents with solubility parameters sufficiently different from those of the asphaltene tested. The kinematic viscosity measures revealed the formation of aggregates at concentrations above the CMC.

The influence of pressure and dissolved gases in petroleum on the efficiency of wax deposition inhibitors

Evaluations of wax inhibitors carried out in laboratories are generally performed on stabilized oil samples, that is, without the presence of natural gas and at atmospheric pressure. Therefore, the effects of two important factors that influence wax solubility – the light fractions and temperature – are not considered, and the results may not reflect what really happens in production lines and facilities.