Electromagnetic Fields in Technology of Processing of Polymeric Materials

2018 ◽  
Vol 22 (11) ◽  
pp. 19-23 ◽  
Author(s):  
A.R. Nasybullin ◽  
O.G. Morozov ◽  
G.A. Morozov

The issues related to the implementation of the process of depolymerizing of waste polymers, initiated by thermal action of an intense electromagnetic microwave field, are considered. The reactions considered are distinguished by the possibility of reducing the initial monomers or oligomers. The required reaction temperatures are achieved by indirect heating due to the presence of carbon thermal converters in the mixture or the use of liquid reagents characterized by high microwave losses. The results of the study of two different mechanisms of depolymerizing, namely the decomposition of the polymer in a glycol medium and thermal decomposition, are shown. The methods of mathematical modeling of the joint problem of electrodynamics and heat conduction are analyzed to estimate the temperature regimes of the processes of thermal decomposition of polymers. Experimental studies are illustrated by examples of the depolymerizing of polyethylene terephthalate, polystyrene and polymethyl methacrylate, the destruction products of which were esters of terephthalic acid, styrene and methyl methacrylate.

2020 ◽  
Vol 65 ◽  
pp. 104162
Author(s):  
Shunchao Li ◽  
Huichun Jiang ◽  
Min Hua ◽  
Xuhai Pan ◽  
Hangchen Li ◽  
...  

2021 ◽  
Vol 1037 ◽  
pp. 369-376
Author(s):  
Maxim Ilyushkin ◽  
Kirill Savelev ◽  
Oleg Krupennikov ◽  
Evgeniy S. Kiselev

The paper presents the results of numerical experimental studies of cutting titanium blanks using mathematical modeling programs, which make it possible to completely repeat technological processes in a computer (digital twin). The LS-DYNA product was used as a program to simulate the process of stock removal from titanium blank. It has been established that the use of this method adequately describes the cutting processes, including with the introduction of the energy of an ultrasonic field into the processing zone, can significantly reduce the duration of experimental research and evaluate the influence of the elements of the cutting mode and design parameters of the tool on the thermal power aspects of the formation of new surfaces of machine parts.


1992 ◽  
Vol 269 ◽  
Author(s):  
Edmund H. Moore ◽  
David E. Clark ◽  
Ronald Hutcheon

ABSTRACTCompact samples of alumina and polymethyl methacrylate have been heated in a 2.45 GHz microwave cavity and by conventional heating in an electric furnace. Various heating schedules have been used to effect the removal of the polymeric binder by thermal decomposition. Dielectric properties, porosity and other physical properties have been investigated in order to better understand the binder removal process in a microwave field. Results of the study emphasize the amount of carbon residuals remaining in the bulk.


2020 ◽  
Vol 11 (3) ◽  
Author(s):  
V. V. Lomaha ◽  
O. Yu. Tsapko ◽  
Yu. V. Tsapko ◽  
O. P. Bondarenko

Reducing the fire prevention of timber is not only an economic task, but also has a social and environmental focus. From economic, technological and environmental perspective, an important problem in ensuring the viability and safe operation of construction sites is the development of fire-retardant coatings for wooden structures. The construction is increasingly looking for new highly effective means of fire protection of wood and wood products which should not only ensure the standardized fire resistance of wood, but also to maintain its operational parameters to solve environmental safety and durability. Studies of the effect of the radiation panel on the ignition of the wood sample have set the parameters of the flame ignition, which makes it possible to influence this process. It is proved that they consist in the formation of a layer of organic material on the surface, which provides heating to a critical temperature, when the intensive decomposition of the material begins with the release of the required amount of combustible gases and their ignition. This makes it possible to determine the effect of fire protection and the properties of protective compositions on the process of slowing down the rate of burning of wood. Experimental studies have confirmed that the untreated sample of wood, under the thermal action of the radiation panel has taken up, the flames spread over the entire surface, which led to its combustion. The application of a fire retardant varnish under the influence of temperature leads to a layer of foam coke and inhibition of heat transfer of high-temperature flame to the material and its ignition. Thanks to this, it became possible to determine the conditions for changing the parameters of combustion and braking during fire protection of wood, by forming a barrier for thermal conductivity. Thus, there is reason to argue for the possibility of directional control of the processes of fire protection of wood by the use of fireproof coatings that can form a protective layer on the surface of the material, which slows down the rate of burning of wood.


2018 ◽  
Vol 13 (3) ◽  
pp. 90-95
Author(s):  
Роман Ли ◽  
Roman Li ◽  
Дмитрий Псарев ◽  
Dmitriy Psarev ◽  
Мария Киба ◽  
...  

Body parts are typical, most material-intensive and expensive parts. When repairing worn out hull details, the costs for repairing equipment are significantly reduced, in comparison with the manufacture of new ones, the consumption of metal, electricity, and environmental pollution is reduced. Unlike many other methods, the methods of restoring body parts with polymeric materials are technologically simple, do not require large energy inputs and high qualification of the personnel. Due to the polymer layer, the stresses in the contact zone of loaded bodies with the bearing raceways decrease and its durability increases, there is no fretting corrosion and the service life of the bearing and body part increases manyfold. The use of polymeric composites can significantly improve the efficiency of restoring body parts. This is due to increased thermal conductivity, thermal and heat resistance, lower cost of composites in comparison with non-filled polymers. A promising direction in improving the consumer properties of the material is the filling of the polymer matrix with nanoscale particles. The nanocomposite based on elastomer F-40 filled with aluminum and copper nanoparticles has been developed and thoroughly studied at the LSTU. The material is designed to restore the landing holes in the hull parts of the tractor equipment. The article presents the results of experimental studies and analysis of deformation-strength and adhesion properties of a nanocomposite, its optimal composition is justified. Comparative results of the study of heat resistance and thermal stability of the F-40 elastomer and a nanocomposite based on are presented. It is shown that the nanocomposite has higher consumer properties than the F-40 elastomer: the strength and endurance are increased to 1.3 times, the heat resistance is up to 123C, the aging coefficients are 1.8 times higher in strength, 1.4 times in deformation.


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