The Effect Of Silica/GO Hybrids On NR Performance

Silica and GO were commonly used in rubber reinforcement.Both of them were difficult to disperse in non-polar rubber matrix,which limits their further application.Silica/GO hybrids obtained great attention since it can overcome the self-agglomeration of GO and silica due to their large surface energy,therefore endowed rubber with excellent electrical and thermal conductivity,mechanical properties,and good dynamic properties.In this paper,Silica/GO hybrids prepared by different methods,such as change the types of modifiers and adjust the amount of GO in Silica/GO hybrids was added into NR latex,making different NR performance.Silica was modified with TESPT,HMIM,TESPT,respectively and GOwas prepared by modified Hummer method,followed by intermolecular hydrogen bonding or electrostatic interaction to fabricate GO/Silica hybrids with sandwich structure.GO was characterized by X-ray diffraction and Raman spectroscopy.Additionally,the vulcanization properties,physical and mechanical properties,and dynamic dynamic properties of the vulcanizates were also studied.Compared with the composites prepared by adding HMIM and Si-69,the composites prepared by adding APES have faster vulcanization speed and higher degree of cross-linking;better rubber-composite filler compatibility;higher stretch Strength,tear strength,and elongation stress;less rolling resistance.With silica firstly modified by 3-aminopropyl-triethoxysilane(APES),graphene oxide(GO)was prepared by modified Hummer’s method.APES-silica/GO(AsGO)hybrids,in which the the amount of silica unchanged and the amount of GO increased in turn,were fabricated through hydrogen bond to reduce the polarity of silica and GO and increase the compatibility between natural rubber(NR)and AsGO.Subsequently,AsGO was incorporated into NR latex.The interaction between GO and silica in AsGO was characterized by X-ray diffraction,Raman,and Zeta potential.It was confirmed bytransmission electron microscopy that the silica was uniformly dispersed on the surface of the GO.The filler–rubber interfacial interaction was thoroughly investigated.The amount of constrained region was quantified through differential scanning calorimetry results,and it showed that the high volume fraction of constrained region is responsible for the strong interfacial interaction.Besides,the mechanical performance,dynamic property,and electrical and thermal conductivity of NR-AsGx were studied.The results showed that the overall performance of NR-AsGx has an optimum value when the GO loading is 1.5 phr,which is due to the good filler dispersion and strong interface interaction.Improving rubber-filler interaction has always been the core of rubber reinforcement.GO was functionalized with bis-[γ-(triethoxysilyl)propyl]tetrasulfide(TESPT),a novel functional agent with dynamic polysulfide bond.The modification of silica was achieved with 3-aminotriethoxysilane(APES)through hydrogen bond.AsTG(APES-silica/TESPT-GO hybrids)were fabricated by an electrostatic assembly,and subsequently,As TG was incorporated into natural rubber(NR)latex to fabricate NR/AsTG composites.The interaction between GO and silica in AsTG was characterized by FTIR and Raman.It was also confirmed by TEM that the silica was uniformly dispersed on the surface of the GO.The filler-rubber interfacial interaction was also thoroughly investigated.The dynamic polysulfide bonds of the grafted TESPT in the TGO can participate in the subsequent vulcanization of NR through polysulfide exchange reactions,thereby forming a tight interaction between GO and rubber.Besides,the mechanical performance,dynamic property and thermal conductivity of NR/silica/GO were studied.Compared with normal NR/AsG system(NR/APES-silica/GO composites),the filler-networking of NR/AsTG composites was significantly reduced,the mechanical properties and thermal conductivity of NR/As TG composites were significantly improved.