| The chemical modified nitrile rubber(Si-NBR) and natural rubber(Si-NR) were prepared using Na H as activator and Et3 Si Cl as modifier by reaction processing method.The silica modified nitrile rubber(Si-NBR) was synthesized in the presence of Na H and Et3 Si Cl by reaction processing method in the Haake torque rheometer. The method avoided the using of The reaction temperature was 90? and reaction time was 30 min. The structure of target product was characterized by Fourier transform infrared spectroscopy. In addition, molecular weight, molecular weight distribution and the gel content were to determine the chain properties of product polymer. The result demonstrated that the group of-C-Si- was successfully introduced into the molecular chains of NBR, the scission and crosslinking of rubber macromolecular chains did not happen in this process. The effect of Na H or Et3 Si Cl content on the curing properties and mechanical properties of Si-NBR was discussed in this paper. It showed that the rest of Na H or Et3 Si Cl would suppress crosslinking reaction during curing and affect the various properties of vulcanizates. Therefore, in order to get the excellent performance, Na H and Et3 Si Cl should be added into the system by the equal amount of substance. The various properties of product polymers were investigated by changing the amount of Na H and Et3 Si Cl in the rule of equal amount of substance. It was found that the optimum amounts of Na H and Et3 Si Cl was 0.04 mol in 100 g nirile rubber. The result showed that Mooney viscosity of Si-NBR decreased; curing reaction extent increased; heat-built of vulcanizates by dynamic fatigue and the deformation extent of vulcanizates by compression fatigue decreased significantly; aging resistance performance and dynamic fatigue performance improved obviously. RPA results showed that Payne effect of Si-NBR decreased greatly and the dispersion of silica improved effectively, compared with that of unmodified NBR.The method for the preparation of Thesilica modified natural rubber(Si-NR) remained the same as that of the silica modified nitrile rubber(Si-NBR). Si-NBR was filled with carbon black or silica. The effect of Na H and Et3 Si Cl content on the various properties of Si-NR was discussed in the paper. The results showed that the Mooney viscosity of Si-NR filled with silica decreased,compared with that of unmodified NR which filled with silica; thecrosslinking density and the content of bond rubber increased obviously. The optimum amounts of Na H and Et3 Si Cl was 0.04 mol in 100 g natural rubber. Under this condition, the tensile strength of Si-NR filled with silica was 27.6MPa, increacing 9.8MPa than that of unmodified NR filled with silica. Compared with unmodified NR filled with silica, the dynamic compression and set heat-built by compression fatigue of Si-NR decreased significantly; Payne effect of Si-NR decreased greatly. Compared with NR, improvement for comprehensive performance of Si-NR reinforced by silica is of much importance for study on green tire. |
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