Synergistical Modification Of Multi-layer Graphene Oxide/Silica And The Properties Of Its Reinforced Natural Rubber Composites

Graphene oxide?GO?,which has unique structure and excellent properties,had became important reinforcing filler of rubber composites.However,there has strong interaction between the GO sheets,which can easy cause stack texture,leading to poor dispersion of GO in the rubber matrix,and the excellent properties of GO can not be exerted.Silica?SiO₂?is environmental friendly filler,which has similar reinforced effect with carbon black.SiO₂ exhibits high fluidity,low expansion coefficient and high filling property.So SiO₂ is one of the major enhanced materials for rubber composites.But SiO₂ has a large amount of silicon hydroxyl groups on the surface,that can lead to the great polarity of SiO₂ and SiO₂ can easily form agglomerate,which limits the application in rubber materials.Therefore,GO and SiO₂ were need to be modified when using them to enhance rubber composites.So this paper was explored some suitable modification methods,which could exhibit the excellent properties of GO and SiO₂.Based on this,the research of this paper had been carried out in the following sections.?1?Multi-layer graphene oxide?MGO?was modified with bis-?P,P-bis-ethylhexyl--diphosphato?-ethanediolato titanatetriethanolamino chelate solution?NDZ-311w?and bis-?g-triethoxysilylpropyl?-tetrasulfide?Si-69?.Then the modified MGO was incorporated into natural rubber?NR?to prepare modified MGO/NR composites.The results show that the MGO-N-S,which was co-modified with NDZ-311w?N?and Si-69?S?,had been exfoliated and dispersed effectively.Also,the interfacial interaction between MGO and the NR matrix was enhanced.Compared with pure Natural rubber?NR?,the MGO-N-S/NR composites'tensile strength,modulus at 300%strain and tear resistance were increased by 26%,98%and 15%,respectively.When the modification methods of MGO was confirmed,the effect of changing the contents of MGO-N-S in NR composites had been studied.The results show that the tensile strength,modulus at 300%strain and tear resistance of MGO-N-S/NR composites could reach the best when added 3 phr MGO-N-S.?2?SiO₂ was modified with Si-69,?-aminopropyl triethoxysilane?KH550?K??and NDZ-311w,and co-modified with NDZ-311w/Si-69 and NDZ-311w/KH550.The results show that when SiO₂ was modified or co-modified by coupling agent,the agglomeration of SiO₂ and the dispersion of SiO₂ in NR matrix were improved.However,the properties of co-modified SiO₂/NR composites were not better then modified SiO₂/NR composites.Based on up work and the frist part work,MGO was exfoliated and dispersed by NDZ-311w,then the modified MGO and SiO₂were connected by Si-69,which could receive MGO/SiO₂ hybrid materials.The results show that the MGO/SiO₂ hybrid materials can form lamella-Spheric structure,which could improve the stack texture of MGO,the practical distribution size of SiO₂ and the interface interaction between MGO/SiO₂ and NR matrix.Compared to MGO/SiO₂?0/50?/NR composites,the tensile strength and modulus at 100%,300%strain of MGO/SiO₂?3/47?/NR composites were increased by 7%,39%and 35%,respectively.The mass loss of the cutting test was reduced 43%.?3?In order to increase the functional application of SiO₂,the antioxidant4-[?4,6-dioctylthio-1,3,5-triazin-2-yl?amino]-2,6-di-tert-butylphenol?antioxidant 565?had been grafted directly on the surface of SiO₂?SiO₂-565?.Or using NDZ-311w as a brige,which could connect the SiO₂ and antioxidant 565?SiO₂-N-565?.The results show that the grafted antioxidant amounts and the dispersion in NR matrix of SiO₂-N-565 were better than other modified methods.After the thermal aging,SiO₂-N-565/NR composites has the best anti-aging effect.When the aging time was three days,the rate of change of elongation at break and tensile strength of SiO₂-N-565/NR were 44.36%and 48.26%,which were far lower than the corresponding rate of change of unmodified SiO₂/NR?77.51%,84.35%?.However,the SiO₂-N-565 only could retard the thermo-oxidative aging process of NR composite,but the results of thermo-oxidative aging were unchanged.