Study Of Preparation And Properties Of The Epdm Reinforced By Carbon Black And Sepiolite

Carbon black,as a kind of reinforcing filler for rubber,provides a guarantee for high performance and application of composite rubber.It will release a lot of greenhouse gases and other environmental pollutants when carbon black has been producted.In addition,the produce of carbon black completely depend on fossil fuels and need higher costs.In recent years,people increasingly pay attention to environmental protection,so it has gradually become a hot research to seek the green and functional rubber filler.Sepiolite is a nanoscale fiber mineral,which is plentiful,with no pollutions,low costs,is expected to reinforce rubber replacing carbon black.Therefore,in this paper,sepiolite modified by coupling agent and carbon were adopted as fillers of EPDM,which has been preparaed a new type of automotive sealing material.The effect of synergistic effect of biphasic filler on mechanical properties of composite and mechanism of reinforcing rubber was discussed.The amount of additives in rubber vulcanization formula was optimized by orthogonal test.On the basis of this,the modification method,ball mill speed and hydrochloric acid concentration were studied,and the optimum modification process was obtained.The sepiolite modified by different types of silane coupling agent and titanate coupling agent had been filled in EPDM.When the content of silane coupling agent KH-570 was 4%,the reinforcement effect was best,which was due to the superior compatibility and dispersion between sepiolite with carbon black.Fourier transform infrared spectroscopy(FTIR)confirmed that the-CH2,-CH3,-C=O and other functional groups had been grafted the surface of modified sepiolite.In addition,the photoelectron spectroscopy(XPS)and thermogravimetric analysis showed that the grafting reaction occurred in the O atom of SiOH on the surface of the sepiolite during the modification.When the content of coupling agent was 3%,chemical grafting rate was about 38.3%.According to the test of sepiolite/carbon black synergisticly reinforcing rubber,when the amount of KH-570 was 4%,the ratio of sepiolite/carbon black was 7:3 and the total amount of fillers were 100 phr,reinforcing effects was best: tensile strength was 14.28 MPa and elongation at break was 301.56%.Compared with the composite rubber reinforced by carbon black,tensile strength,although slightly lower,but the elongation increased by 125.6%,which were more than the national standard on the mechanical properties of automotive sealing material twice.Thereby,it significantly reducing the production costs.Dynamic thermomechanical test analysis(DMA)showd that the descent rate of storage modulus of composite rubber would slowed down,when the modified sepiolite partially replaced carbon as filler.With the increase of the amount of sepiolite,the peak of loss factor tan? of composite rubber decreased and moved to the high strain direction,which indicated that the ability of the composite rubber network to bear the deformation would been improved due to the addition of sepiolite.