Создание эффективных композиционных полимерных материалов конструкционного назначения и разработка технологии получения деталей хлопкоперерабатывающих машин

Аннотация

Topicality and demand of the subject of dissertation. The increased interest in the development of effective composite polymer materials for manufacturing mechanical engineering parts with improved tribological characteristics, including cotton processing industry, due to the current requirements and defines the prospects of development of innovative technologies. Raw cotton plays an important role in the economy of Uzbekistan. Therefore increase of efficiency of production of cotton through complex mechanization of all processes, starting with cotton collecting and finishing by its processing, improvement of working capacity and productivity of used machinery and mechanisms with preservation of natural indicators of raw cotton is the main technical and economic task, actual for scientists, engineers and designers of Republic. The problem can be solved by the use of composite polymeric materials (CPM) in manufacturing of working bodies of cotton processing machines. In order to implement these measures the development and implementation of innovative technologies in the field of composite materials, providing improvement of technological equipment for processing of raw cotton are important and in demand. Molecular-mechanical-electrical theory, explaining the processes occurring upon contact the material with cotton fiber, is considered to be one of the fundamental to modern material science and tribology. Based on this theory, a comprehensive study of the processes occurring in the "polymer-filler", "polymer-cotton" and "composite-cotton," reveals the regularity of formation of interfacial interaction in polymer compositions depending on the type of polymer binders, the nature, content and structure of fillers and cotton raw, to develop effective antifriction, antifriction wearproof CPM that provide increased efficiency and effectiveness of the working bodies of the cotton-ginning and cotton proceeding machinery. In this regard development of optimum structures and effective resource-saving technologies of receiving of antifriction and wearproof CPM on the basis of local raw material resources and establishment of optimum technological parameters of manufacturing the parts and details for machinery, in particular, for machinery of the cotton processing industry, is an actual problem. The research work is in demand and is orientated on ensuring implementation of the Resolutions of the President of the Republic of Uzbekistan PP-916 of 15.07.2008 "On additional measures to stimulate introduction of innovative projects and technologies into production" and the Cabinet of Ministers of the Republic of Uzbekistan PP-832 of 07.04.2008 "On program of modernization and reconstruction of the cotton industry for 2007-2011" Purpose of research is the development of composite polymeric materials that provide the physical, mechanical and tribological properties of cotton processing machinery parts. Scientific novelty of dissertational research consists in the following:: the regularities elicitated of change in physical-mechanical and tribological properties of composites from the type and content of polymers and fillers. Mineral fillers - talc, kaolin, wollastonite at their optimal content of 10-30 mas. p. improve the antifriction and physical mechanical properties, fluidity of the polymer composition, reduce shrinkage during the formation of these parts; fiber glass and cotton lint, increase strength properties and friction factor, reduce intensity of wear process, raise stability of composites to thermomechanical influences at the expense of their reinforcing, thus optimum doses fillers in a composition are 10-40 mas. p.; carbon-graphite fillers - graphite and carbon black, reduce friction factor, increase wear process, raise heat - and electrical conductivity, reduce temperature and size of a charge of the static electricity, arising in a zone of a friction of rubbing pairs working structures of machines, thus the optimum maintenance fibrous fillers in compositions makes 5-10 mas. p.; the considerable effect of strengthening of operational characteristics of CPM was revealed when using the mechanically activated fillers which basis is made by the found specific interactions of polymer with a surface of the dispersed fillers; effective structures of some antifrictional and is antifrictional-wearproof CPM are developed and laws of change physicomechanical and tribotechnic properties depending on technological modes of their moulding under pressure which allow to establish optimum technological parameters of their formation with high physicomechanical and tribotechnical properties are established; recommendations for rational use of optimum technological parameters of formation taking into account potential possibilities of increase of resources and operability of materials were developed; recommendations for rational use of optimum technological parameters of formation taking into account potential possibilities of increase of resources and operability of materials were developed; optimum technological parameters (melting temperature, specific pressure of injection, form temperature, time of endurance of details in shape, cooling time) of manufacturing of monolithic wearproof details of rubbing pairs of working bodies of cotton processing machinery were defined. CONCLUSION 1. Physical and chemical bases of creation of the antifrictional and antifrictionwearproof composite polymeric materials, combining in structure fibrous, mineral and carbon-graphite fillers, by detection of regularities of a variation largely elastic strengthening characteristics, factor of a friction and wear from type and concentration of separately taken fillers are developed, including and a mechanically activated condition, and also their synergetic mixes. 2. Optimum structures of antifrictional and antifriction-wearproof polypropylene and polyethylene composite materials (APEC-1, APEC-2, AWPEC-1, AWPEC-2, APPC-1, APPC-2, AWPPC-1, AWPPC-2), providing their best functionally important physical-mechanical and operational properties and, respectively, effective work in the conditions of their interaction with cotton raw in the form of pin workers of bodies of cotton processing machinery and mechanisms are developed. 3. Consistent patterns of change of antifrictional and antifriction-wearproof properties of composite polypropylene and polyethylene materials are determined at frictional interaction with cotton raw from type and the maintenance of fillers. It is revealed that the best indicators on factor of a friction have the polyolefins filled with carbon-graphite fillers. Mineral fillers increase factor of a friction and at the same time reduce intensity of wear process, except for such fillers, as talc and kaolin which have lamellar structure and at which use decrease in factor of a friction is observed. Effective decrease in intensity of wear process of polymeric composites is observed also at introduction of fillers of the fibrous type providing high durability and stability of a material to thermomechanical influence. The established dependences laid down in a basis of development of technology of receiving products on the basis of the developed optimum structures of CPM. 4. The technological line is developed for receiving CPM and on their basis of details of rubbing pairs of working bodies of cotton processing machinery which allows to receive the composites packed in the form of tablets. 5. Results of IR-, EPR-spectroscopy and x-ray researches established existence of specific interactions polymeric binding with organic and inorganic components in CPM. It is revealed that the mechanical activation of fillers (in particular a kaolin, soot, fiber glass) leads to emergence on a surface of various type of the active radicals promoting strengthening of interaction of polyolefins with fillers which regulation allow to vary largely structural and kinetic activity of fillers. Elastic strengthening characteristics of composites with mechanically activated fillers exceed traditional composite polymeric materials of identical structure more than for 15-20%. 6. Researches on optimization of technological parameters of molding under the pressure of CPM are carried out. It is established that formation physicalmechanical and the CPM tribotechnical properties is in direct dependence on technological parameters at their molding under pressure. Thus the most essential influence put melting temperature and specific pressure of injection of a material, and duration of endurance of composition in shape under pressure, time of endurance of products in shape at their cooling and form temperature - insignificant influence. 7. The carried-out comparative tests of developed composite polymer peg details of working bodies of cotton proceeding machines showed that their application increases wear resistance in 1,5-1,8 times, productivity of machines - for 7-14 %, reduces power consumption - for 5-8 %, mechanical damage of fibers - for 0,12-0,28 %, damage of seeds - for 0,16-0,32 %. Economic effect from application of details from antifrictional and antifriction-wearproof composite materials of working bodies of cotton processing machines at Buka cotton plant is 125 million soums (2013).