Preparation And Properties Research Of Graphene,Fiber Reinforced Silica Aerogel

Graphene,as nanofillers,was added into SiO2 matrix to prepare the SiO2/graphene composite aerogel monoliths through ambient pressure drying and freeze drying methods.The results show that the addition of graphene make the hydrophobic property,mechanical property and thermal performance of SiO2 aerogel improve a lot.At the same time,the glass fiber reinforced SiO2/graphene composite aerogels were prepared through ambient pressure drying,and the hydrophobic property,mechanical property and thermal property were studied and characterized.The results are as follows:Reduced graphene oxide,as the raw material,was stirred with silica sol to prepare SiO2/graphene composite aerogel on the basis of sol-gel technology and ambient pressure drying.SEM and pore structure analysis show that SiO2/graphene composite aerogel remain nanoporous structure and mainly distribute in 2-20nm.When the dosage of rGO is 5%,the contact angle of SiO2/graphene composite aerogel reach up to 151°,which show excellent hydrophobic performance.According to the stress-strain curve,the addition of graphene makes the brittleness of SiO2 aerogel decreased.The SiO2/graphene composite aerogel present toughness instead of fragility the pure SiO2 aerogel do.Moreover,when the dosage of rGO is 5%,the compressive strength of SiO2/graphene composite aerogel is 0.091 MPa.SiO2/graphene composite aerogel was prepared through freeze drying method.The results show that the content of graphene oxide has a large influence on the performance of SiO2/graphene composite aerogel.When the graphene content is 2%,SiO2/graphene composite aerogel has pretty low density of 0.096 g/Cm3.The SiO2/graphene composite aerogel possess good mechanical properties and thermal performance.When the graphene content is 5%,the compressive strength improved a lot than pure SiO2 aerogel,reach up to 0.55MPa.Moreover,When the the graphene content is 2%,the thermal conductivity of SiO2/graphene composite aerogel can be as low as 0.037W/(m · K).Finally,the glass fiber reinforced SiO2 aerogels and the glass fiber reinforced SiO2/graphene composite aerogels were studied through ambient pressure drying.The density of composite materials ranges from 0.194g/cm3 to 0.226g/cm3.The glass fiber reinforced SiO2/graphene composite aerogels possess good hydrophobic performance,its contact angle and water absorption rate can reach 141° and 0.83%.At the same time,composite materials have good heat insulation performance and mechanical properties.When the graphene content is 0.25%,the thermal conductivity can be as low as 0.032W/(m ·K)at room termperature.When the graphene content is 5%,the compressive strengths of glass fiber reinforced SiO2/graphene composite aerogels are 0.093MPa(10%strain),0.369 MPa(25%strain),2.135 MPa(50%strain).