Study On The Effect Of Temperature On Mechanical Properties Of Rubber And Its Mechanism

In this paper,polybutadiene rubber(BR)and hydrogenated nitrile rubber(HNBR)were used as the main body to investigate the physical and dynamic mechanical properties of vulcanizates with different reinforcement systems and vulcanization systems in the temperature field.By testing the resilience,hardness,tensile strength,elongation at break,stress relaxation and dynamic mechanical properties of vulcanizates,polar and nonpolar rubbers were explored The different response of the microstructure of the rubber molecular chain,chemical crosslinking network and physical crosslinking network to the temperature can provide theoretical basis and method guidance for the development of rubber products in extreme environment.The effect of temperature on the physical and dynamic mechanical properties of BR vulcanizates with different reinforcing systems and different curing systems was studied.The results showed that with the increase of temperature,the resilience and hardness of BR vulcanizates with different carbon black content and different curing systems increased,the tensile strength and elongation at break decreased,the tensile stress at 50% and 100% increased,the rate of stress relaxation accelerated,and the storage modulus increased.The higher the content of carbon black,the higher the tensile strength,elongation at break and retention of tensile strength of BR vulcanizate at high temperature.The tensile strength and elongation at break of BR vulcanizate with high content of polysulfide crosslinking bond were higher at high temperature,while the constant extension stress and strength retention rate of BR vulcanizate with high content of carbon-carbon crosslinking bond were higher at high temperature.The effects of temperature on the physical and dynamic mechanical properties of HNBR vulcanizates with different carbon black content and different curing systems were studied.The results showed that the hardness and tensile strength of HNBR vulcanizates with different carbon black content and different curing systems decreased with the increase of temperature.The resilience and elongation at break increased from 25? to 50?,then decreased gradually.After stress relaxation for 20 minutes,the proportion of equilibrium stress decreased gradually,and the storage modulus decreased gradually.The higher the carbon black content,the higher the tensile strength and strength retention of HNBR vulcanizate at high temperature.The tensile strength and elongation at break of HNBR vulcanizate with sulfur vulcanization system were higher at high temperature,while the constant extension stress and strength retention rate of HNBR vulcanizate with peroxide vulcanization system were higher at high temperature,and the rate of stress relaxation was slower.The mechanical properties of BR and HNBR were compared with each other with the increase of temperature.The response of polar and non-polar rubber to temperature was investigated by RPA,and the mechanism of the change of micronetwork structure of the two kinds of rubber was explored.The results showed that at room temperature,the intermolecular force of polar rubber was larger than that of non-polar rubber,but it is more sensitive to temperature.Increasing temperature made the modulus of polar rubber decrease faster than that of non-polar rubber.Carbon black in non-polar rubber has better dispersion and more content of bond rubber,which makes the retention rate of non-polar rubber better than that of polar rubber with the increase of temperature.In the process of temperature rising,the change of micronetwork structure in rubber material is different,and the change of macro physical and mechanical properties is the result of many factors.