The Research Of Nano-filler Silica For Rubber

VWith the increasingly serious environmental problems,the green tire with high efficiency,energy saving and environmental protection characteristics has become a research hotspot.It can effectively reduce automobile fuel consumption and reduce the harm caused by combustion of fossil fuels on the environment.The technical difficulty of the "green tire" is that it is difficult to balance the rolling resistance,wear resistance and wet skid resistance,and the addition of inorganic filler silica can effectively balance the "magic triangle",which is also the core technology.However,there are still some problems,such as large particle size and surface hydroxyl groups,which lead to poor hydrophobicity and dispersion in rubber.Therefore,it is critical to reduce the particle size and improve the hydrophobic properties of silica products.In this paper,silica particles with smaller particle size were prepared by improving the preparation process,and their hydrophobic properties were improved by grafting organic compounds,in addition,the effect of various modifiers on rubber properties was also investigated:(1)Nano silica was produced via hydrothermal method,using sodium silicate as raw material,PEG 6000 as surfactant,at the same time NN4H2PO4 solution as latent acid reagent.Among them,NN4H2PO4 solution is weak acidity,and under the closed hydrothermal environment,the acidity increases and accelerates reaction,while PEG 6000 can be adsorbed on the surface of silica and restrain the growth of particle size.Through the structural characterization and performance test,the effects of temperature,concentration of silicon source,ratio of PEG 6000 and the amount of NN4H2PO4 solution(pH)on the structure and morphology of silica were systematically investigated.By optimizing the preparation conditions,the controlled preparation of silica was achieved.The silica particles with smaller particle size(primary particle size:12 nm,second particle size:66 nm),larger specific surface area(141.132 m2/g),higher oil absorption value(2.2 mL/g)were prepared.(2)In order to further improve the yield of silica,nano silica was produced via low temperature precipitation method under 0?,using sodium silicate as raw material,Twelve alkyl benzene sulfonate(LAS)as surfactant,citric acid as latent acid reagent.The adsorption of LAS and silica can effectively restrain the growth of particle size,moreover,the presence of benzene rings and long alkyl chains increased the hydrophobic properties of silica products.Through the structural characterization and performance test,the effects of temperature,concentration of silicon source,and the ratio of LAS on the structure and morphology of silica were systematically investigated.By optimizing the preparation conditions,the controlled preparation of white silica was achieved.The silica particles with smaller particle size(primary particle size:15 nm,second particle size:215 nm),larger specific surface area(144.646 m2/g),higher oil absorption value(2.2 mL/g)were prepared.(3)in order to further improve the solubility of silica with rubber,modified nano silica was produced via orthogonal experiment method,using vinyltriethoxysilane(KH151),stearyl alcohol,oleyl alcohol as modifier.Among them,stearyl alcohol and oleyl alcohol are long alkyl chain modifier,low price,and can improve the performance of hydrophobic silica,and the oleyl alcohol contains double bond,can strengthen the effect of vulcanization.The influence of experimental conditions on hydrophobic properties of silica was investigated.The modified silica with smaller particle size(below 20nm),larger specific surface area(140m2/g or more)and lipophilic value of 20%was prepared.The modified silica was expanded to prepare and mix with rubber to test its rubber properties.The influence of modifiers on rubber properties was investigated and compared with commercial silica.The results showed that the positive sulfur time of the modified compound rubber was significantly reduced.The proper curing time of compound rubber modified by long alkyl chain modifier is obviously higher than that of short chain modifier.The wet skid resistance and wear resistance of the modified compound rubber products have been improved slightly,which is slightly better than that of commercial products.The rolling resistance of the modified compound rubber is obviously decreased,and the double bond has a greater influence on the rolling resistance of the compound,and the rolling resistance of the modified product is lower than that of the commercial silica compound.