| In this paper,the cure characteristics,static mechanical properties,dynamic mechanical properties and aging properties of EPDM were studied from filling system,reinforcing system,reactive agent,pre-dispersing filler and secondary vulcanization process.The effect of filling system,reinforcing system,reactive agent,pre-dispersing filler and secondary vulcanization process on tear resistance at high temperature were emphatically investigated.Firstly,the effects of kaolin,wollastonite and mica powder on the cure characteristics,static mechanical properties,dynamic mechanical properties,multiple network structure and properties of EPDM vulcanizates were studied.The results showed that the three fillers had adverse effects on the static mechanical properties of EPDM vulcanizates.With the increase of the fillers,the tensile properties and tearing properties of EPDM vulcanizates showed a downward trend,but the decrease of mica powder was small.Considering comprehensively,mica powder can be selected as filler in EPDM formulation with 15 phr fillers to obtain better tear resistance at high temperature,better processing performance and lower cost.In order to improve the static and dynamic mechanical properties of EPDM and enhance the high temperature properties and optimize the formulation design,the effects of new fillers CNTs,GO and ZDMA on the properties of EPDM vulcanizates were studied in this study.The results show that when the dosage of CNTs is 3 phr,the comprehensive high temperature tearing property of the compound is the best;when the dosage of GO is 0.24 phr,the tearing strength reaches the maximum at100?,which is 89.4%higher than that of the control group.Considering comprehensively,CNTs can be selected as reinforcing filler in EPDM formulation,and the filling fraction is 3 phr,so as to obtain better high temperature tear resistance.Furthermore,the effects of ZMDA and PCG on the comprehensive properties of EPDM vulcanizates were also studied from reactive agent and pre-dispersed fillers.The results showed that when the dosage of ZDMA was 7 phr,the crosslinking density of EPDM was 9.891*10-5mol/cm3,which was 26.7%higher than that of the control group.At this time,the tearing strength of EPDM at room temperature was58.07 MPa and at 100 was 30.88 MPa,which were 20.8%and 32.8%higher than that of the control group respectively.When the dosage of PCG was 1 phr,the tearing strength of EPDM reached the maximum,53.6%higher than that of the control group at 100?and 125?respectively.The tear strength increased by 43.4%and 7.6%at150?.Considering comprehensively,7 phr ZDMA can be selected as vulcanizing agent in EPDM formulation,1 phr PCG can be selected as reinforcing filler to obtain better high temperature tear resistance.Finally,the effect of secondary vulcanization process conditions on the properties of EPDM vulcanizates was studied.The results show that the secondary vulcanization process can improve the hardness,resilience,compression set rate,high temperature properties and odor of EPDM vulcanizates.Considering comprehensively,the performance of EPDM vulcanizates can be better improved by secondary vulcanization at 150?for 24h. |
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