EFFECT OF FILLERS ON THE CHARACTERISTICS OF SINGLE-COMPONENT SEALANTS BASED ON SILYLATED POLYURETHANES

The work presents the results of studies of the complex of technological properties (curing rate and viscosity of the sealant) and performance properties (strength, breaking elongation, hard-ness, adhesion to various surfaces) of single-pack (single-component) sealants based on silylated (silane-functional) polyurethanes in the presence of various fillers. The possibility of wide variation of properties of the resulting sealants is shown. In the absence of literature data on the influence of fillers on the properties of silylated sealants, studies were carried out on the effect of the compo-sition on the technological and performance properties of sealants. As fillers, calcium carbonate, talc, titanium dioxide, aluminum powder, chrysotile asbestos were used. It is established that the addition of aluminum powder enables to obtain compositions with low viscosity (up to 0.4 MPa & BULL;s) and high breaking elongation (up to 220%). Asbestos-filled compositions have high breaking strength (4.9 MPa) and lowest breaking elongation (less than 40%). The mass loss of the filled samples was studied by thermogravimetric analysis. The greatest effect without loss of physical and mechanical characteristics was shown by filling with titanium dioxide, talc and aluminum powder. The weight loss of the samples at a heating rate of 5 deg/min at a temperature of 200 & DEG;C was less than 1.3%, so the introduction of fillers increases the thermal-oxidative resistance of the sealants. The adhesion properties of the compositions were investigated when sealants were applied to sur-faces made of steel, polycarbonate, viniplast, slate. The revealed regularities allow us to purpose-fully develop sealants based on silane-functional polymers with the necessary set of properties in accordance with the customer's requirements.