| Silicone rubber is a special and interesting material,its unique polysiloxane molecular chain structure gives it irreplaceable properties for other types of rubber.Nowadays,with the rapid development of artificial intelligence,medical equipment,and electronic devices,silicone rubber has huge application prospects in these fields.Graphene has a variety of excellent physical and chemical properties due to its bizarre two-dimensional structure,and it is highly expected to be used as a new type of filler to prepare high-performance composite materials.However,as a carbon nanomaterial,graphene shows very poor compatibility with silicone rubber,and the direct compounding of graphene and silicone rubber will cause the performance of silicone rubber to decrease.Therefore,before adding graphene,it is necessary to modify graphene to improve its compatibility with silicone rubber.In the second chapter of this dissertation,firstly,use AEAPTMS to reduce and modify graphene oxide.One ends of AEAPTMS are connected to graphene,meanwhile,the other ends form a self-assembled monolayer(SAM)under the action of hydrogen bonds.With the assistance of SAM,polysiloxanes were grown on the surface of graphene to obtain uniformly silanized graphene AGO-TEOS and carried out a series of characterization of AGO-TEOS.Subsequently,AGO-TEOS was added as the filler to the silicone rubber to prepare silanized graphene/silicone rubber composite material,which has high mechanical properties,and explored the effect of different silanization degrees as well as different amounts of AGO-TEOS on the properties of composites.After silanization,AGO-TEOS exhibits perfect compatibility with the silicone rubber matrix.Through the AFM PF-QNM mode,it can be observed that AGO-TEOS still maintains a two-dimensional structure in the rubber matrix.The molecular chain of silicone rubber can be adsorbed on the surface of AGO-TEOS to form an interface layer,which greatly improves the mechanical properties of silicone rubber.When the addition amount of AGO-TEOS is 5 wt.%,the tensile strength of the composite is 6.30 MPa,which is 15.75 times that of pure silicone rubber,and the elongation at break is 99.31%.Constructing a three-dimensional graphene network in a rubber matrix is an effective method to prepare conductive rubber.By mixing GO aqueous solution and natural rubber/styrene-butadiene rubber latex,then hydrothermal reduction and self-assembly have successfully prepared conductive rubber with high conductivity.However,silicone rubber is hydrophobic and difficult to disperse in water.Therefore,in Chapter 3,firstly,a GO/SR mixed emulsion that can be uniformly and stably dispersed is prepared by high-speed shear emulsification,the size of the SR latex particles is about 20μm.Then,ascorbic acid is added as a reducing agent,GO was wrapped with SR particles and hydrothermally reduction self-assembles into 3D RGO/SR gel.After drying and vulcanizing,a conductive graphene/silicone rubber composite material was successfully obtained and explored the influence of different RGO content on volume conductivity is discussed.When the amount of graphene added is 4 wt.%,the 3D RGO/SR composite exhibits a conductivity of 3.38×10-4 S·m-1.In general,this dissertation uses graphene as a filler to prepare two different graphene/silicone rubber composites,which have achieved the enhancement of silicone rubber from the aspects of mechanical properties and electrical conductivity. |
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