The paper studies the dynamic-mechanical characteristics of styrene-isoprene-styrene, polybutyl methacrylate, thermoplastic polyurethane block copolymers and their blends by dynamic mechanical analysis. It is found that blending of several types of polymers allows to extend the range of effective vibration absorption. A combination of polymers with high damping properties over a wide temperature-frequency range was determined. The influence of vibration frequency on dynamic-mechanical properties of composites has been investigated.
Keywords: polymer composite material, dynamic mechanical analysis, polybutyl methacrylate, thermoplastic polyurethane, styrene-isoprene-styrene block copolymer, vibration absorption, damping material, glass transition temperature
Vulcanization is a technological process that transforms plastic rubber into rubber. As a result of vulcanization, the shape of the product is fixed, and the material becomes more durable, hard and elastic. The purpose of the article is to determine the effect of octyl phenol-formaldehyde resin on the vulcanization parameters and to identify its optimal amount for the development of vibration-absorbing materials based on butyl rubber. The effect of a vulcanizing agent (octyl phenol formaldehyde resin) on the properties of the rubber compound during vulcanization was established. As a result of the study, the kinetics of vulcanization and the effect of various components on the properties of the rubber compound, such as elongation at break, conditional tensile strength and specific damping ability, were studied. This study is conducted in order to find the optimal rubber for placement in a seismic damper used in buildings and structures.
Keywords: vulcanizing group, vibration absorbing material, butyl rubber, rubber compound, vulcanization, octyl phenol formaldehyde resin, seismic damper
The technological process of manufacturing self-adhesive radio-absorbing materials is considered. The technological mode of manufacturing radio-absorbing materials consists of two operations – the preparation of a mixture and the production of radio-absorbing materials from the resulting mixture. An important step is mixing the mixture. The quality of the radio-absorbing material depends on the quality of the mixture.
Keywords: mixture, mixing time, scanning probe microscope, microstructure study
Currently, one of the most promising and cost-effective methods of seismic isolation is the use of passive energy dissipation systems. The research carried out in this article focuses on the use of a new hybrid energy dissipation device that combines a parallel layer of an inexpensive viscoelastic material and a metal component. Typically, the viscoelastic material in such systems is attached to steel shock absorbers with an adhesive. In this article, the behavior of a viscoelastic material is studied when it is attached to a metal component without the use of glue, being held only by friction and pressure. The influence of the compression force on the elastic and damping properties of a viscoelastic material arranged in a seismic damper has been established, and the pressing force has been determined, which ensures the optimal functional properties of the viscoelastic material.
Keywords: earthquake, seismic safety, damper, thermal expansion, viscoelastic material, rubber compound, rubber, resin, polymer, vibration, seismic isolation
This article discusses the most common materials and how they are used to protect against ionizing radiation used for medical purposes. Comparison of technical and economic devices for the construction of a protective fence from the described radiation protection materials is presented. The effectiveness of the use of self-adhesive polymer radiation-shielding materials for protection against insulation with voltage up to 100 kV has been established.
Keywords: gamma radiation shielding, radiation shielding, EPDM, metal oxide, barite, polymer composites
This article is devoted to the problem of development of damping polymer materials with high damping properties in a wide temperature range. The purpose of this article is to study the loss factor and strength of polymer materials based on ethylene-vinyl acetate when additional polymers in the form of rubbers are added to them. The leading method to investigate this problem is the method of dynamic mechanical analysis, which allows to obtain information about changes in the dynamic properties of polymeric materials subjected to oscillating loads depending on frequency and temperature. According to established experimental dependences, it was possible to define the type of additional polymer expanding the temperature range of effective damping and increasing tensile strength of composites based on ethylene-vinyl acetate. The percentage content by volume of the additional polymer was established at which its efficiency on the dynamic and mechanical properties of composites on ethylene-vinyl acetate basis will be greatest.
Keywords: ethylene-vinyl acetate, polymer, chlorobutyl rubber, nitrile butadiene rubber, strength, damping, glass temperature, dynamic mechanical analysis