| In this paper, the mechanical properties, stress relaxation and dynamic mechanical properties of rubber damping material were studied in the hot oxygen environment, stress environment (including tensile stress and compressive stress) as well as the medium environment, and rubber damping material life was predicted in the hot air aging environment.Thermal aging behavior of butyl rubber (ⅡR) vulcanizates was investigated by hot air aging test machine. The results showed that crosslink density, tensile strength, the modulus at definite elongation and hardness of IIR vulcanizates increased firstly and then decreased as the aging time increased, while the elongation at break declined rapidly and then tended to be leveling off. Dynamic mechanical thermal analyzer (DMA) results showed that the loss factor (tanδ) peak and damping temperature range (tanδ≥0.7) decreased firstly and then increased with the increase of aging time; Under the same aging time, the higher the aging temperature was, the wider the damping temperature range was.Tensile fatigue aging behavior of IIR vulcanizates was studied by using tensile fatigue testing machine. The results showed that tensile strength and elongation at break of IIR vulcanizates decreased after the first increased as the fatigue number of increase, while the modulus under200%elongation decreased gradually; crosslink density reduced rapidly then gradually tended to a constant; the σ10/σ0decreased firstly and then increased. With the increase of strain, the shear storage modulus (G’) and the shear loss modulus (G") decreased gradually, while the tan8increased gradually, and all the values tended to decrease and all of them were higher than them before fatigue, with the increase of the number of tensile fatigue. The value of tanδ peak and damping temperature range increased at first and tended to a constant as the fatigue number increased.Compression fatigue aging behavior of IIR vulcanizates was studied by compression fatigue testing machine. Temperature at the bottom and the hardness of IIR vulcanizates increased and decreased respectively as the compression fatigue time extended. Permanent deformation was positively correlated with the extension of compression time. The platform of G’ gradually decreased in the low temperature section (<-50℃) as the compression fatigue time extended. The G" peak at-47℃ significantly reduced with the increase of compression fatigue time; As the strain increased, G ’and G" decreased and the values became even lower after compression fatigue. The tanδ peak value and damping temperature range increased linearly with the extension of compression fatigue time.The3#standard oil aging behaviors of nitrile rubber (NBR) vulcanizates were studied by oil experimental tank. The results showed that, as the immersion time extended, the tensile properties of NBR vulcanizates were gradually reduced, the hardness decreased firstly and then gradually tended to be a constant, quality swelling rate and immersion time were positively correlated and σ10/σ0increased as the immersion time extended. G1decreased with the increase of strain. The longer the immersion time was, the lower the value of G1was, as well as G". G" of NBR vulcanizates (not soaked) decreased after the first increased with the increase of strain, while G" of the sample after soaking decreased slightly. Tan8increased at first and tended to be a constant as the strain increased, and the longer the immersion time was, the lower the platform of tan8was. With the extension of immersion time, the G’ abrupt change area moved to low temperature, the peak of G" decreased and the maximum tanδ peak increased gradually. The damping temperature range of NBR vulcanized was broaden the2℃after soaked1day, but it became almost the same as the immersion time extended.Storage life of IIR vulcanizates was predicted through the method of straight-line of kinetic curve. With tensile strength as the evaluation index, in the hot air aging environment, the predicted life of IIR vulcanizates at room temperature was14years. With damping temperature as the evaluation index, the predicted life of ⅡR vulcanizates at room temperature was17years. Damping temperature range could also be used to predict the service life of the rubber damping material and the results were approximate with the prediction of conventional performance, but the coefficient K of kinetic equation must be positive. |
