Effect of water on the strength of rubber bonding with adhesives based on reactive oligomers

The effect of water redistribution between SKEPT-40 rubbers and reactive adhesives based on SKN-18KTR mixtures with ED-20 on the strength of adhesive compositions was studied. Water vapor sorption isotherms were measured. It was shown that the water content of rubbers during their scheduled conditioning at a humidity of 65–70% leads to the spontaneous redistribution of water between the substrate and the adhesive. This process is accompanied by the retardation of the formation of the adhesive network structure and, as a consequence, by a fall in the strength of adhesive joints. The mechanism of formation and failure of SKEPT-40-(SKN + ED-20) adhesive joints was revealed. A procedure for calculating the amount of water capable of redistributing between the elements of adhesive joints is proposed. Rubber conditioning parameters that ensure the required quality of bonding the rubbers with SKN-18KTR-ED-20 compositions were determined.