Peculiarities of the production of materials based on polysulfide oligomer-polymerizable compound compositions cured in the presence of manganese oxide

Abstract

96Polysulfide oligomers are finding ever widening application as sealants for glass units and building structures [1]. However, the known building sealants, as a rule, do not possess high and stable adhesion to substrates, especially to glass. One can increase the strength of bonding with substrates by modification of thiocol compositions with polymerizable compounds. Papers [1,2] show the regularities of the influence of mono and bifunctional unsaturated oilgoesters on the curing process, structure, and properties of thiocol sealants. At the same time, to the best of our knowl edge, there are no literature data on the effect of poly functional unsaturated compounds. Therefore, the goal of present work was to study the effect of acrylic monomers and oligomers (and their mixtures) previ ously unexplored in the formulation of thiocol com positions, on the properties of elastomers. EXPERIMENTALAs polymerizable compounds, oligoacrylates of Sar tomer production (United States) were used (Table 1). As polysulfide oligomers, liquid thiocols of types I, II, and NVB 2 (GOST (State Standard) 128112-80) were selected. It was assumed that the branching of a thio col structure would facilitate the increase of the extent of material cross linking owing to the formation of additional cross bonds.The compositions were prepared using a PE 8300 high rate stirrer. The adhesion of materials upon a break was defined according to the following proce dures: for a metal-polymer-metal bond, GOST (State Standard) 209-75 (method A) using metallic discs (10 mm in thickness and 35 mm in diameter), for a concrete-polymer-concrete bond, GOST (State Standard) 28574-90 on concrete plates (100 × 100 × 50 mm) of Portland cement of M35 trademark; and, for a glass-polymer-glass bond, GOST (State Stan dard) 28574-90 on glass plates (100 × 100 × 50 mm). The parameters of a spatial network were determined by sol-gel analysis, and the cross linking coefficient was calculated using the equation γ = 2/(S + ), where S is the content of a sol fraction. The resistance to the action of aggressive media was defined according to GOST (State Standard) 9.068-76 and 9.083-78. RESULTS AND DISCUSSIONTaking into account the quite high reactivity of oli goacrylates and polysulfide oligomers, the possibility of physical and chemical interactions between them cannot be ruled out. Implicitly, the physicochemical interaction can be judged from the build up of the composition viscosity without addition of an initiating system. Table 1 shows the values of viscosity for the mixtures cured for 3 days.It was established that, as a rule, the addition of acrylic and methacrylic monomers leads to the reduc tion of a mixture viscosity. Thus, due to the low inten sity of physicochemical interactions proceeding between the components, the addition of 2 phenoxy ethyl acrylate (or 2 phenoxyethyl methacrylate) has a diluting effect on the composition. Therewith, despite S Abstract-The effect of the physicochemical structure of polymerizable compounds on the curing process, structure, a...

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“…Polysulfide can be viewed as a type of polymer bearing atoms of sulfur in its molecular chains 1 . Polysulfide possesses a profusion of incomparable merits, such as showing superb properties at low temperatures 2 , being stable in a wide assortment of solvents and water 3,4 and the ability to stick to catholic surfaces 5 , and has been applied in numerous industrial applications ranging from adhesives 6 , sealants 7 and coatings 8,9 . In addition, the disulfide-bond-owning polymer can be used to synthesize self-healing materials out of the occurrence of S−S links in its main chains [10][11][12] .…”