EFFECTS OF FILLERS ON PROPERTIES OF ONE-PART POLYURETHANE SEALANTS WITH PRESENCE OF A LATENT CURING AGENT

Abstract

In this study, the effects of fillers on the technological properties of polyurethane sealants and the physical and mechanical properties of air moisture curing sealants are investigated. The sequence of loading the components in the dissolver, factoring in the presence of a latent curing agent, is demonstrated. It was found that when filling within 20-80 parts weight per 100 parts weight of the pre-polymer, the general complex of physical and mechanical properties remains high. With the introduction of mineral dispersed filler, the tear strength increases, but the relative elongation at break decreases. The increase in the tensile strength occurs up to a certain limit, after which there is a decrease in the strength of the sealant. It was shown that based on the oil absorption value of the fillers, the type and the amount of a filler for the sealant can be evaluated, as oil absorption directly depends on the particle size, surface area and particle shape of the filler. It was observed that for maintaining high physical and mechanical properties of the composite and the optimum viscosity of the sealant, it is preferable to combine two kinds of fillers with different oil absorption. It was established that the application of fillers with high and low oil absorption has a positive effect on the technological and performance properties of sealants. The filler with high oil absorption contributes to the thixotropy of the sealant, while the filler with low oil absorption allows to form a more highly filled composite while preserving the high strength characteristics.