RESEARCH OF MIXED POLYMER COMPOSITIONS BASED ON ACRYLIC MONOMER

Abstract

The study of structural and mechanical properties of acrylic compositions based on methyl methacrylate, modified with polymers of the vinyl series. It was found that compositions of the mixed type based on methyl methacrylate have a high modulus of elasticity in the vitreous and highly elastic state. The observed effect is due to antiplastification as a result of chemical grafting of a polymeric modifier to macromolecules of polymethyl methacrylate. The effect of modifying polymer additives on the dynamic modulus of elasticity, speed of sound, tangent of the angle of mechanical losses at room temperature was studied in a wide range of concentrations. It is established that the concentration dependences of the structural and mechanical properties of monomer-polymer compositions are extreme. In the region of low concentrations, maxima are observed, which depend on the type and composition of polymer modifiers. At low concentrations of polymer modifier (up to 15 wt. h.) and at concentrations of about 50 wt. including the processes of ordering and chemical grafting lead to the compaction of molecular packaging in the system (the speed of sound increases and mechanical losses fall). These processes predominate over the process of classical plasticization, which leads to a decrease in the amount of intermolecular interaction. At other concentrations of polymer modifiers PS and PSM the second process prevails, which leads to a decrease in the speed of sound and an increase in mechanical losses due to increased molecular mobility. The introduction of the polymer modifier in the original monomer makes the composition unsuitable in terms of application to the surface of the elements intended for subsequent bonding. Therefore, in our opinion, it is advisable to limit the introduction of polymer additives not more than 20 wt. hours per 100 wt. including the original monomer – methyl methacrylate. Modification in this limitation (range from 5 to 15 wt. H) not only maintains technological advantages but also provides compared to the unmodified composition of high elasticity of the adhesive material, which is a very important condition for minimizing deformation of the adhesive seam of reinforced concrete structures. Additional recommendations on the technology of production and use of monomer-polymer acrylic compositions as adhesive compositions are given, taking into account the amount of polymer modifier introduced.