Preparation,Structure And Properties Of Styrene-Butadiene Rubber/Graphene Functional Composites

Styrene-butadiene rubber(SBR)is an important synthetic rubber.The application range of SBR could be greatly expanded by improving its electrical conductivity,thermal conductivity and mechanical properties.Graphene is a multifunctional carbon nanofiller which is expected to significantly improve the electrical conductivity,thermal conductivity,and mechanical properties of SBR at a low loading level.For the preparation of SBR functional composites,it is a key issue to explore the uniform dispersion and ordered distribution of graphene in SBR.In order to improve the dispersion of graphene,graphene hybrid fillers with different compositions and structures were prepared,which were composed of graphene and silica or graphene and carbon nanotubes(CNTs).These graphene hybrid fillers could be uniformly dispersed in SBR and significantly improve the properties of SBR composites.Then,with the help of SBR foam as a template,graphene was orderly distributed in the SBR,and the performance of SBR composites was remarkably improved at a low graphene loading.Here,graphene hybrid fillers were prepared and graphene filler networks were formed by a template method,and the relationship between structure and properties of their SBR composites was studied.The main contents are as follows:The synergistic enhancement effect of silica and graphene oxide(GO)in SBR was studied.After modified with 3-aminopropyltriethoxysilane,silica was decorated on GO surface to fabricate a silica-GO hybrid by an electrostatic self-assembly method.The composition and structure of the hybrid were characterized,then the effects of the type and content of fillers on the properties of SBR composites were investigated.The hybrid was well dispersed in SBR and effectively improved the mechanical properties and thermal stability of SBR composites.As the content of the hybrid increased,the dielectric constant of the SBR composites increased,while the dielectric loss,keeping at low values,was less affected by the hybrid content.The enhancement of the thermal conductivity of SBR with mesoporous silica and reduced graphene oxide(r GO)was investigated.With cetyltrimethylammonium chloride as a template,mesoporous silica was coated on the surface of GO.Then,a mesoporous silicar GO hybrid was prepared by hydrothermal reduction.The sandwich structure of the hybrid and the mesoporous characteristics of the silica were characterized.The influence of the content and type of fillers on the thermal conductivity of SBR composites was studied.The hybrid significantly improved the thermal conductivity of SBR composites at a low loading.The reasons for enhancement of the thermal conductivity of SBR were analyzed.The structure and properties of stretchable and electrically conductive SBR composites were investigated.A r GO-CNT hybrid with sandwich structure was prepared by hydrothermal reduction method,and its composition and structure were characterized.The influence of the composition and amount of the hybrid on the electrical conductivity of SBR composites were investigated,it was found that a filler network with interconnecting reduced graphene oxide and carbon nanotubes was formed by the hybrid,which could effectively improve the electrical conductivity of SBR composites.SBR composites were stretchable and able to maintain their electrical conductivity at low strains.The reasons why the SBR composites maintain their electrical conductivity under tensile deformation were discussed.A compressible and electrically conductive SBR foam was prepared and the relationship between electrical conductivity and compressive strain was investigated.An SBR/GO(GSBR)foam with open-cell structure was prepared by vacuum freeze-drying method.Then,GO was adsorbed on the inner wall of the GSBR foam by vacuum assisted impregnation and followed by in situ reduction with hydrazine hydrate.and a compressible and electrically conductive GSBR/r GO foam was prepared.The improvement of electrical conductivity of the GSBR/r GO foam was benefit to the ordered distribution of reduced graphene oxide in the GSBR foam,enabling efficient construction of a conductive filler network.The influence of solid content of GSBR latex on the cell structure and morphology of GSBR foam was investigated,and the effect of compression treatment on the structure and morphology of GSBR/r GO foam was studied.The GSBR/r GO foam was able to return to its original state after large strain compression,the change law of electrical conductivity of GSBR/r GO foam with compressive strain was studied,and its causes was analyzed.A method for significantly increasing the electrical conductivity of SBR at a low filler loading was investigated.With the open-cell structured GSBR foam as a template,r GO and CNT as fillers were adsorbed on the inner wall of the foam,and then the foam was hot pressed to obtain SBR composites.The distribution of the fillers on the inner wall of the foam was studied and compared with the filler distribution in the composites.The electrical conductivity of SBR composites was greatly increased at low filler loadings.This is because the fillers were orderly distributed in the SBR composites,forming an efficient threedimensional conductive network.Finally,the influence of SBR foam structure on the properties of SBR composites was studied.It was found that the conductivity of SBR composites can be controlled by changing the distribution of cells in the foams.