Study On The Friction Characteristics And Medium Resistance Of High And Low Temperature Resistant Sealing Materials

Rubber sealing materials have a wide range of applications and increasingly demanding performance requirements.In order to prepare multi-functional and high-performance rubber sealing materials,it is difficult to meet the use requirements using a single rubber material.Therefore,two or more rubber materials can be used to improve performance.In this paper,the effects of vulcanization system,plasticizer system,and acrylonitrile content on the mechanical properties,low temperature resistance,and oil resistance of nitrile rubber(NBR)were studied first,and the appropriate vulcanization system,plasticizer,and acrylonitrile content of NBR were determined.The mechanical properties,compression set,high temperature resistance,and low temperature resistance of ethylene butadiene rubber(EBT)and ethylene propylene rubber(EPDM)were also compared.Then,NBR was modified by EBT,and the effects of different NBR/EBT blending ratios on the mechanical properties,high and low temperature resistance,and oil resistance of the rubber compound were studied.In addition,the phase compatibility of NBR and EBT modified by using carbon nanotubes(CNTs)and zinc methacrylate(ZDMA)was also studied.Finally,the effects of different amounts of polytetrafluoroethylene(PTFE)on the mechanical properties,self-adhesiveness,and friction coefficient of the rubber compound were studied,as well as the effects of in-situ mixing method on the properties of the rubber compound.The synergistic effect of PTFE and graphite on the mechanical properties,self-adhesiveness,and friction coefficient of the rubber compound was also studied.The research results show that:(1)By studying the effects of vulcanization system,plasticizer system,and acrylonitrile content on the properties of NBR,it can be found that NBR with peroxide vulcanization system has better low-temperature resistance,and TR10 can reach-57.2 ℃;As the amount of plasticizer increases,the low temperature resistance of NBR gradually decreases.For each increase in the amount of plasticizer of 10 phr,TR10 can be reduced by 5 to 10 ℃.The low temperature resistance effect of plasticizer JH-95 is slightly better than that of TP-95;With the increase of acrylonitrile content,the mechanical properties,oil resistance,and aging resistance of NBR gradually improve,but the low-temperature resistance gradually deteriorates.(2)By comparing the performance of EBT and EPDM,it was found that EBT has superior processing safety and tear resistance compared to EPDM,and EBT has better self-adhesion and resistance to high and low temperatures.The TR10 of EBT can reach-49.9 ℃,while the TR10 of EPDM is-42.4 ℃,and the self-adhesion of EBT is twice that of EPDM.(3)By studying the effect of the blending ratio of NBR and EBT on the properties of the compound,it can be found that with the increase of the amount of EBT,the mechanical properties,compression set resistance,and oil resistance of the compound gradually decrease,while the low temperature resistance,high temperature aging resistance,and ozone aging resistance are improved.Each increase in the amount of EBT by 15 phr decreases the TR10 of the compound by 1-2 ℃,and when the blending ratio of NBR/EBT is 70/30,the comprehensive properties of the compound are the best.Adding CNTs and ZDMA improved the compatibility of NBR and EBT,increased the tear strength by 5 to 10 k N · m-1,and improved the compatibility of the rubber compound.(4)By studying the effect of PTFE on the performance of NBR,it can be found that with the increase of the amount of PTFE,the mechanical strength of NBR first increases and then decreases,and the friction coefficient first decreases and then increases.When PTFE is added to 6phr,the friction coefficient is the lowest,with the dynamic and static friction coefficients of 0.33 and 0.57,respectively.However,the self viscosity gradually decreases,with each increase of 3phr,the self viscosity of PTFE decreasing by about 2.0N,and the wear volume and compression set gradually increasing,When the dosage is greater than 6 phr,the increasing trend gradually slows down.After the addition of modified PTFE,the mechanical properties and self-adhesiveness of the rubber compound were improved,and with the increase of the dosage,the self-adhesiveness first increased and then decreased,reaching the maximum at 3 phr.However,the friction coefficient,wear volume,and compression set of the rubber compound were larger than those of the unmodified rubber compound.When PTFE and graphite are used together,with the increase of graphite content,the mechanical properties first increase and then decrease.When the graphite content is 2phr,the mechanical strength is the highest.For each increase in graphite content,the self viscosity decreases by 2 to 5 N,and the friction coefficient decreases by about 0.1.The wear volume gradually increases with the increase of graphite content,but the increasing trend of friction coefficient and wear volume gradually stabilizes when the graphite content is greater than 8 phr.This experiment has studied the high and low temperature resistance,friction characteristics,and medium resistance of rubber materials,making rubber materials have multi-functional and high-performance properties,and expanding the application field of rubber.