Study On Preparation And Properties Of Wide Temperature Range And Low Hysteretic Damping Plate For High-Speed Rail Based On Styrene Butadiene Rubber

Currently,the WJ-8 fastener vibration damping gasket of high-speed rail on the market mainly includes polyurethane gasket and EPDM gasket,etc.These gaskets have good vibration damping performance,but their use temperature range is narrow,not suitable for use in low temperature environment.In view of this situation,low styrene content SBR is selected as the rubber matrix in this topic.On this basis,the influence of foaming formula and foaming process on the performance of SBR microporous vibration damping pad is studied,and the best foaming formula and foaming process is determined.The SBR micropore vibration damping plate with low temperature resistance,vibration damping and mechanical properties meeting the requirements of railway standard TB/T 3395.5-2015 was successfully prepared.Then on this basis,the influence of pre-vulcanization time and other technological conditions on various properties of the rubber vibration damping plate used for BR9000/SBR1502 was preliminarily explored.By evaluating the damping performance of the rubber damping pad,the system is expected to produce a rubber damping pad with better low temperature resistance.The research content of this topic is divided into two parts:1.First of all,according to the low temperature resistance index of railway standard,from the glass transition temperature,brittleness temperature,crystallinity,rubber cost and other aspects to determine the rubber matrix of this topic as SBR,and screen out the low temperature resistance of low styrene content of the self-synthesis of SBR-10 and SBR-15,the two kinds of rubber were tested by DSC.The results showed that SBR-10 had better low temperature resistance,but SBR-10 raw glue could not be produced in large quantities at present,so it was excluded.The basic characterization of SBR-15by DSC,XRD and DMA shows that there is no obvious crystallization of SBR-15.The T_gvalues of SBR-15 vulcanized rubber measured by DSC and DMA are-57℃and-41℃respectively.The T_gvalues under dynamic conditions are higher than-50℃.At this time,the sample was in an approximate static state,and the static stiffness change rate of the damping cushion plate with SBR-15 as matrix was 10%at-50℃,which met the railway standard requirements,so the rubber matrix was determined to be Shengxi’ao SBR-15.The effects of reinforcing system,vulcanization system and foaming system on the microstructure and properties of SBR foaming materials were studied.In comprehensive consideration of improving the mechanical properties of rubber foaming materials,improving the vibration damping properties of foaming materials and reducing the cost of raw materials,the optimal dosage of white carbon black VN3 was determined to be 30 phr,and the vulcanization system was sulfur/peroxide combined system.The optimal dosage of peroxide odourless DCP is 1 phr,and the dosage of foaming agent OBSH-75 is 2 phr.Under this formula,the vibration damping performance of SBR foaming material is at a better level,and the static stiffness is 24.8k N·mm^-1,which meets the index requirements.The static stiffness ratio is 1.37,slightly higher than the static stiffness ratio index of 1.35.Based on the above formula research,the influences of process factors such as pre-vulcanization temperature,pre-vulcanization time,post-vulcanization temperature,post-vulcanization time and foaming rate on the microstructure and properties of SBR foaming materials were further studied.The foaming process was determined to be three stages:pre-vulcanization,foam-vulcanization and post-vulcanization.In consideration of optimizing the performance of rubber gasket and improving production efficiency,the pre-vulcanization process conditions of SBR rubber foam material were determined as 130℃×15 min,foaming vulcanization conditions as 150℃×23 min,and post-vulcanization conditions as 170℃×1 h.Under this technological condition,the mechanical properties,vibration damping properties and the change rate of low temperature static stiffness of SBR rubber vibration damping cushion meet the requirements of railway standard TB/T 3395.5-2015.The static stiffness is 23.8 k N·mm^-1and the static stiffness ratio is 1.31.2.DMA test with BR9000/SBR1502 adhesive shows that its T_gis-73℃,which has good low temperature resistance.Preliminary foaming process exploration and performance evaluation were carried out on the rubber damping plate based on BR/SBR and rubber matrix.The influences of pre-curing time and foaming rate on the properties of BR/SBR rubber damping plate were studied.The optimal pre-curing condition was determined to be 125℃×13min,and the tensile properties and static stiffness of rubber damping plate met the requirements.However,the ratio of static and static stiffness is higher than the index requirement,so further formulation and process optimization are needed.