Keyword: «physical and mechanical properties»

This paper presents the results of comparative studies of the physical and mechanical properties of ultra-high molecular weight polyethylene and modified polymer composite materials (PCM) before and after bench full-scale tests at the climatic test site in Yakutsk. It is established that in the conditions of the sharply continental climate of Yakutia, ultra-high molecular weight polyethylene and a composite containing 5 wt. % of carbon fibers of the brand "Belum" are aging by the fourth month of exposure. In this regard, ultra-high molecular weight polyethylene was modified not only with carbon fibers to increase the physico-mechanical and tribotechnical parameters, but also a stabilizer of the SO-4 brand produced by NIOH SB RAS was introduced. Based on the conducted studies, it was found that the additional modification of the UHMWPE-UV composite with a stabilizer of the CO-4 brand leads to a slowdown in the photo-oxidative processes of the composite in the open air, which has a positive effect on the preservation of physical and mechanical parameters for a long time under the influence of adverse climatic factors. This fact allows us to predict the high performance of products made of the developed material in the conditions of the sharply continental climate of Yakutia.

The results of a study of the conditions and duration influence of the carbon nanofibers (CNF) synthesis on the physico-mechanical characteristics of polyethylene composites based on them are presented. CNF were obtained by the catalytic pyrolysis of hydrocarbons. It has been established that the introduction of CNF doped with nitrogen leads to decrease in the deformation-strength characteristics of the composite. Samples of composites containing CNFs with the shortest synthesis time (up to 40 min) were characterized by the best abrasive resistance.

The influence of the mixing regime on the properties of low temperature oil-resistant rubbers based on the blend of BNKS-18AMN butadiene-nitrile rubber and GUR 4113 ultra-high molecular weight polyethylene was studied. Different ways of introducing of UHMWPE into the rubber mixture are considered: by mixing before and after the introduction of the main ingredients of the rubber mixture at temperatures up to 80°C (below the melting point of UHMWPE), as well as by preliminary high-temperature (160°C) mixing of rubber and UHMWPE. It was found that preliminary high-temperature mixing of rubber with UHMWPE leads to a decrease in the viscosity of the rubber mixture, as well as a reduction in the scorch time and the achievement of the optimum vulcanization, but does not lead to significant changes in the physical and mechanical properties and oil resistance of vulcanizates.

It is shown that the stabilization of natural soils with ANT additives together with Portland cement causes a directed change in their properties and contributes to the development of new materials with an improved set of physical and mechanical characteristics for their use in the production of small building materials. The dependences of the compressive strength of samples from stabilized soils on the initial moisture content and the amount of additives introduced have been established. An optimal composition has been developed, characterized by improved compressive strength, water and frost resistance, recommended in the manufacture of building materials for low-rise construction.

Currently, polypropylene pipes are quite widely used and their use in construction will only grow in the future. In areas of cold climate, their use is significantly constrained by temperature restrictions during installation and transportation. Physical and mechanical properties of polypropylene are given in the information sources mainly at a temperature of 20 ° C. To develop a technology for the construction of water supply systems at low temperatures, it is necessary to study the change in the properties of the polypropylene pipe material depending on temperature. This paper presents the results of tensile and impact strength tests of pipe polypropylene. A significant decrease in the relative expansion of the material of a polypropylene pipe with a decrease in temperature has been established.