INFLUENCE OF MICROSPHERES ON PROPERTIES OF AGGRESSIVE RESISTANT RUBBERS

Abstract

The aim of the work is to study the effect of hollow corundum, glass and pomegranate ceramic microspheres on the rheometric characteristics of aggressive resistant rubber mixtures and the physicomechanical parameters of their vulcanizates to determine of the content of fillers of this type, which provides an improvement in the priority properties of products and, as a result, an increase in their durability. The objects of research were two rubber mixtures intended for compression molding and injection molding. The compression molding mixture is based on a combination of nitrile butadiene, isoprene and butadiene-α-methyl styrene caoutchoucs with colloidal silicic acids as the main fillers. And the injection molding mixture is based on a combination of synthetic isoprene and butadiene rubbers filled with chalk, P234 carbon black and carbon 100. We used hollow corundum (HMC-L), glass (MS-V), and pomegranate ceramic (MVMD-170) microspheres. The rheometric properties of the rubber compounds were evaluated by the values of the minimum and maximum torques, the duration of the induction period, the time to reach the technological optimum, and the maximum vulcanization rate. When testing vulcanizates, conditional tensile strength, elongation at break, tear resistance, hardness, abrasion and rebound elasticity were determined. Priority indicators were also determined that correlated to the greatest extent with the durability of the products during operation - relative changes in conditional tensile strength and elongation at break, hardness after heat aging in air and standard liquid SZhR-1, change in mass of samples after swelling in industrial oil I-20A and Nefras S-80/120. For a mixture for compression molding, the effect of the type of microspheres introduced at a dosage of 5 parts by mass per 100 parts by mass caoutchoucs, on the properties of unvulcanized mixtures and vulcanizates was studied. It was found that the rubber mixture with glass microspheres is somewhat below in vulcanization activity, and its vulcanizate in terms of abrasion resistance, heat aging, especially in air, is inferior to two mixtures and rubbers with corundum and pomegranate microspheres. In the second mixture, we tested corundum microspheres with a dosage of 3.0 to 7.0 parts by mass per 100 parts by mass of caoutchoucs while reducing by the appropriate amount of carbon black. It was found that with an increase in the dosage of microspheres, a decrease in the vulcanization activity of the mixture, minimum and maximum torques, and also their difference is observed, which indicates a slight decrease in the degree of crosslinking of rubbers. The consequence is an increase in relative lengtheningof the vulcanizates. To the least extent, this effect manifests itself with the introduction of corundum microspheres in a dosage of 3 parts by mass. Thus, the advantage of rubbers with microspheres is reduced abrasion, higher tear resistance while maintaining resistance to the action of physically and chemically aggressive environments at the level of rubbers that do not contain microspheres.