The paper presents the results of a study of the dilatometric properties of thermoplastic elastomer nanocomposites based on mixtures of random polypropylene, nitrile butadiene rubber, a compatibilizer - copolymer of polypropylene with maleic anhydride. Nanosized bentonite particles were used as a filler. The concentration of bentonite nanoparticles was varied in the range of 1.0-20 wt %. The values of the free and occupied specific volumes of nanocomposites were determined depending on the temperature and concentration of bentonite. The mechanism and kinetic regularities of the crystallization process of nanocomposites are established.
The article deals with the influence of the concentration of butyl rubber and vulcanizing agents on the process of reactive extrusion of elastoplastics based on a mixture of thermoplastic polyolefins. The mechanic-chemical synthesis of dynamically vulcanized elastoplastics was carried out in the process of reactive extrusions. Single screw extruder with ratio L / D = 24 consists of 4 zones: loading zone, compression zone, dosing zone, extruder head. The number of turnovers of the screw was regulated using an asynchronous engine. The head is equipped with a slotted console enabling to obtain continuous sheets 2 mm thick and 100 mm wide. As thermoplastic polyolefins there was used the polyethylene of low density, polypropylene. Vulcanization of polymer mixtures was carried out using the dicumyl peroxide and sulfur. The mechanochemical synthesis of elastoplastics was carried out at different temperatures of the zones of material cylinder and extrusion pressure. The results of the study of the influence of extrusion process parameters on the melt flow rate of elastoplastics were presented. For a mixture of polyethylene and butyl rubber of low density the optimum temperature for zones of the material cylinder varied within 100 150 ° C, and the extrusion pressure was 5.2 7.0 MPa. For a mixture of polypropylene and butyl rubber the temperature regime varied within 140-210С and pressure of extrusion-7.2-9.4 МPа. To add elastoplastic properties to the polymer mixtures, vulcanizing agents such as dicumyl peroxide and sulfur were introduced into their composition. Selective influence of vulcanizing agents on the nature of changes of technological parameters of reactive extrusion and melt flow index was investigated. It found that dynamic vulcanic elastoplastics with unique compatibility of structures and properties can be obtained in at concentrations of dicumyl peroxide 0.5 wt.% or sulfur5.0wt.%. It revealed that dynamic vulcanic elastoplastics with unique compatibility of structures and properties can be obtained in the concentration of dicumyl peroxide 0.5 wt.% or sulfur 5.0wt.%. It established that the concentration of butyl rubber in
The work deals with the results of analytical review of the development and research of polymer composite materials with improved electro-physical and physical-mechanical properties. It found that the selection of special fillers, their variation by quantity and particle sizes in the polymer matrix can essentially affect the electro-conductivity of material and thereby regulate their electret properties on the whole. It revealed that the use of traditional fillers of carbon-black, graphite, minerals, metals, etc. in the composition of thermoplastics, reactoplastics and rubber makes it possible to prepare antistatic products, electromagnetic protective coatings, resistors, various types of current-conducting materials. The use of various lightweight fillers allows preparing lowdensity composites with higher physical-mechanical and electret properties. The spheroplastics based on siloxane elastomer began gaining a larger popularity. There is the data on carbon-blackfilled composite materials based on polyolefins which, at definite ratios, allow preparing the electroconductive products. A certain place in the review is given to the use of highly dispersed metal powders for the improvement of the electret characteristics of composites. Much attention is paid to the investigation of nanofilled composites with the use of large set of the dispersed minerals. The use of hybride polymer nanocomposites opens up new perspectives for their wider use in the production of current-conductive materials. The possibility of chemical binding of mineral filler particles with polymer matrix using the binders with conjugated double bonds provides innovative approaches to the creation of high-strength and heat-resistant electroconductive composites. It becomes obvious that the most perspective direction of preparation of materials with high electret properties must be based on mechanical-chemical synthesis of composite materials.
Рассмотрено влияние концентрации бутадиен-нитрильного каучука и технологического режима литья под давлением на комплекс основных свойств эластопластов на основе термопластичных полиолефиновполиэтилена низкой плотности и полипропилена. Использование пероксида дикумила в качестве сшивающего агента позволило в процессе «монотрем» технологии получить динамически вулканизованные эластопласты с улучшенными физико-механическими и технологическими свойствами.
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