Preparation And Applications Of Graphene Aerogel Composities

As a star of materials in the rencent years,graphene have inspired the researchers because of its unique structure and a series of excellent properties.In the many derivatives,the three-dimensional graphene not only retain the excellent mechanical,electrical and thermal properties of two-dimensonal structure,and has a large specific surface aera an a porous structure that can be controlled,which shows excellent potential in many fields,such as adsorption,energy storage,catalyst carrier and sensors.In this paper,we use the modified Hummers method to obtain the graphene oxide(GO)by oxide the nature flake graphite.And use it as the precursor to prepare two kinds of graphene aerogels by chemical crosslinking and chemical reduction self-assembly.We also explored its application in epoxy resin based composities and environmental pollution,the main contents were as follows:(1)DDM modified graphene aerogel(DGA)was obtained by self-assembly and freeze-drying using conventional curing agent DDM as chemical crossling agent and ammonia as adjubant.Then the different DGA content of epoxy resin composities was prepared by filling E51 epoxy into the DGA with different density.Through the test of DGA/EP composites,we first found that when the content of DGA is as low as 0.42wt%,the conductivity of DGA/EP is 0.48S m-1,which was 12 orders of magnitude higher than that of pure epoxy,and the conductivity increased with the increase in the content of DGA.The other thermal conductivity and thermal decomposition temperature also showed a similar law.In the curing process of epoxy resin composites,the presence of DGA promotes the curing reaction and decreased the activation energy of the resin system.And we demonstrate that this noncovalent bond and covalent bond exist between the DGA and the pure epoxy resin matrix by non-isothermal DSC and Raman spectra.Because of the increase of DGA content,the CTE values of DGA/EP composites before and after the glass transition temperature are greatly reduced,and the glass transition temperature and storage modulus were increased with the increase in the content of DGA.(2)A novel ultra-light graphene aerogel with highly repeatable compressibility was successfully synthesized via a low cost and viable approach.In specific,the graphene aerogel exhibited a super absorption capacity for oil and various organic solvents up to 350 times of its own mass after thermal annealing,which was much higher than the most reported absorption materials,and excellent reusable properties in absorption-combustion,absorption-distillation,and absorption-squeezing cycles.In addition to the excellent absorption capabilities,the unique graphene aerogels also possessed other significant performances,such as ideal hydrophobility,satisfactory fire-resistance,and strain-sensitive electrical conductivity.More importantly,in comparison with the usual reduction temperature for GO,e.g.180 ?,our fabrication approach only involved a relatively low temperature(90 ?),at which the successfully reducing GO with ammonia solution was realized assisted by freeze-drying and thermal annealing.The viable method and unique performance advantages endow the resulting graphene aerogels with important and broad applications such as oil absorption,energy devices and pressure sensitive sensors.