Study On Damping Modification And The Relationship Of Nr Network Structure-damping Properties

Natural rubber is widely used in all kinds of rubber products because of its good comprehensive properties,but its lag loss is small and the effective damping temperature is low at low temperature.It is not good for the use of products and its use range is very narrow.Therefore,it needs to be modified by rubber blending to broaden its effective damping temperature range and improve its performance.In this paper,the natural rubber NR is used as the rubber matrix.By adjusting the vulcanization system,adding small molecular plasticizer and the molecular chain structure characteristics and using other rubber in the three directions to improve its damping performance.First,the effects of different vulcanization systems(traditional sulphur vulcanization system,semi effective sulphur vulcanization system,effective sulphur vulcanization system)on the various properties of NR were studied.When the dosage of accelerator is 1.2 copies,the mechanical properties of the vulcanizates are ideal,the compression permanent deformation is large,and the fatigue temperature rises.while high sulfur content makes the mechanical properties of the rubber obviously decreased,the compression permanent deformation and the fatigue temperature increase,and the high sulfur content will reduce the comprehensive properties of the rubber,but the high sulfur content will decrease the comprehensive properties of the rubber.The damping performance is obviously improved.With the decrease of the ratio of sulfur and accelerator,the mechanical properties of the vulcanizates become worse,the elasticity of the system is lower than that of the traditional vulcanization system,the compression permanent deformation is small,and the fatigue temperature rise decreases.For semi effective sulphur vulcanization system,the mechanical properties,lag loss and heat generationof NR vulcanizate are between EV and traditional vulcanization system.Secondly,the effect of small molecular plasticizer and phenolic resin reinforced resin on the properties of NR was studied.The results showed that adding plasticizer would improve the processing property of the rubber,but the compression permanent deformation would increase.The increase of the amount of bio oil would improve the mechanical properties of the vulcanizate and the damping of the rubber.Performance and aromatic oil can reduce mechanical and damping properties,but adding bio oil and aromatic oil will increase fatigue temperature.The addition of bio modified asphalt can improve the shortcomings of these two plasticizers,and improve their mechanical and damping properties.The addition of phenolic resin can effectively improve the hardness of vulcanizate,increase the hysteresis loss and improve the damping property.Finally,NR is modified with SBR,CR,NBR,POE and silicone rubber to improve the damping loss factor and effective damping temperature range of the blend.The results show that with the increase of SBR content,the mechanical properties of the blends have different degrees of influence,HED increases first and then decreases,and the damping property is improved,and the compression fatigue temperature is improved.The compression permanent deformation increases first and then decreases when the rise increases.When the blending ratio is 70/30,the compression permanent deformation is the largest.The content of CR will reduce the mechanical properties of vulcanizates,increase the fatigue temperature and increase damping.When the CR content is 30 phr,the compression permanent deformation of vulcanizates is the largest.NR and CR blend,the metal oxide vulcanization system will reduce the mechanical properties of the blends,but have little effect on the damping property,permanent deformation and compression fatigue temperature rise.The increase of NBR content in the system will reduce the mechanical properties of vulcanizates,increase damping capacity,and make compression permanent deformation and fatigue temperature rise gradually increase.Because POE is a thermoplastic elastomer,blending with NR will increase the elasticity and mechanical properties of the blends,and the lag loss increases first and then decreases,but it is still lower than the pure NR HED.After the use of NR and silicone rubber,the increase of the content of silicone rubber will reduce the mechanical properties of the blends,but the damping property is improved,the compression permanent deformation and the fatigue temperature increase,and theregulation of the peroxide vulcanization system will produce the same result.