| There are many different types of EPDM which have different microstructure and rubber performance. Besides, the main-chain of EPDM is completely saturated, which gives it good heat resistance performance, and its vulcanizates can be used at 150℃ in a short period of time, so the EPDM is widely used in pipes, belts and other rubber products. However, with the working environment of EPDM products getting worse and worse, it′s very necessary to optimize the integrated performance of EPDM working at a higher temperature.This paper compared the performance of different types of EPDM and studied the effect of microstructure on the basic properties of the rubber. The results showed that the curing speed got slower, the crosslinking density and mechanical strength increased with the increase of ethylene content, meanwhile the heat resistance of the vulcanizates improved. The mechanical strength increased, the flexible fatigue resistance and heat resistance decreased with the increase of ENB content. The curing speed of the DCPD was faster than the ENB significantly, and the flexible fatigue resistance of DCPD was better than ENB while the heat resistance of ENB was better because of the high crosslinking density of ENB.The EPDM blend with EPM, and its basic properties compared with another kind of EPDM which with the same content of ENB. It turns out that, there are no obvious change in the curing rate, but the crosslinking density of the blend are larger. The fatigue resistance of the blend, especially the crack growth resistance significantly better than the EPDM, the thermal oxygen aging performance was equal. In summary, the fatigue resistance of the blend is much better than the EPDM with the same content of ENB.This article has studied the effects of different vulcanizing agents on the performance of EPDM filled by S, EDMA, TAIC, respectively. Meanwhile, the influence of paraffin oil content on the properties of EPDM was also studied. The results showed that, compared to EDMA, when TAIC served as the co-curing agent, the curing rates of compounds got faster, the cross link density was lower, the fatigue resistance was better and the heat resistance of both was better. The elongation at break and tear strength of the vulcanizates improved significantly, fatigue resistance improved while the heat resistance properties decreased when replaced TAIC or EDMA with equivalent sulfur. The RPA results of frequency scanning showed that, the crosslinking density of vulcanizates increased, the storage modulus increased and the loss factor decreased, while the storage modulus decreased and the loss factor increased when replaced TAIC or EDMA with equivalent sulfur. The use of paraffin oil had improve the processing properties of the EPDM compounds significantly, but the curing rate got lower, the crosslinking density, tensile strength and hardness of the vulcanizates decreased as well. The amount of paraffin oil had a best value for the fatigue life of vulcanizates and the increase of paraffin oil amount made the heat resistance of vulcanizates decreased slightly.The fatigue resistance property of EPDM/EPM blend and EPDM which with the same content of ENB was studied, in order to find the reason of the difference of their fatigue performance. The results showed that: the dispersion of carbon black in the blend is better than in EPDM, the G′ and G″ are smaller when the strain is bigger, the decreasing range of G″ is much bigger, this shows that in the process of dynamic fatigue the viscous resistance of EPDM/EPM blend is much smaller. The tensile fatigue process of vulcanizates were also studied, it turned out that crosslinking density of the blend did not change obviously in the process of fatigue, with the increase of the number of fatigue the E′ showed a trend of decline,meanwhile the tanδ increased and the loss leak widened. |
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