Study On Compounding Of Eddmbased High Speed Railway Pad

In this thesis, the influence of EPDM microstructure, sulfur content, accelerator content, reinforcement agent type and amount on properties of EPDM-based high speed railway pad was studied.The results show that EPDM with higher ENB content has a faster cure rate and better mechanical properties; EPDM with higher molecular weight had lower heat build-up and lower compression set; EPDM with higher ethylene content is easier to crystallize at a lower temperature and have a bad damping at low temperature. So K9950C is the best choice for EPDM railway pad application.Sulfur content has a strong influence on property of EPDM. Higher sulfur content has a higher curing rate and higher crosslink density, the mechanical properties is also increased, the compression set is decreased and the fatigue resistance can be improved, but the ageing resistance is deteriorated as the sulfur content increases. In regard of all the properties, the sulfur content of 1.2 phr is the best dosage for EPDM railway pad application.200% modulus and other mechanical properties can also be improved by increasing accelerator content without the deterioration of ageing resistance.The addition of N990 can apparently decrease the mooney viscosity and improve the processing property. As the content of N990 increase, the elasticity improved and the compression set and temperature rise decreased, so the service life of rubber pad is extended. As the addition of N990 increases, the damping property is improved resulting from the extended damping area in the low temperature.Silica can improve the mechanical property and elasticity of rubber compound. The tensile strength,200% modulus, hardness and compression resistance is improved. Silica can decrease the compression temperature rise.Mechanical property is improved by increasing filler content, but the elasticity and fatigue resistance are deteriorated.