Preparation Of Graphene Powder And Graphene Aqueous Dispersion

Since the single-atom thickness of the two-dimensional planar structure of graphene was found in the laboratory in 2004,it attracted people's attention.The excellent performance of graphene and its potential applications in various fields have led to extensive research upsurge in the world.But how to achieve the high quality,large-scale production of graphene,is still a major problem need to be solved.As a result,introducing alternative technic or ameliorating current process are considerable strategies to address this problem.The main contents of this paper include the following parts:(1)By improving the original preparation method,high yield and high quality graphene powder was obtained.Instead of traditionalstep in open system,LPAN(Liquid polyacrylonitrile oligomers)has commenced to pre-sintering in nitrogen atmosphere,which is capable of avoiding excessive mass loss.In addition,occupancy of defect structure of graphene was restrained as well.Hence,both quality and quantity was improved eventually.It has important significance for the industrial production of grapheme.(2)Designed a simple and effective ball milling method: Mechanical division with chemical modification method,the reaction of graphene with potassium hydroxide occurs by ball milling to fabrication graphene aqueous dispersion,It's concentration is 0.5 mg/ml.Precisely,graphene was been exfoliated by ball-milling.During this physical process,activated carbon core,such as radicals and ions,has been forged from broken C-C bond,which reinforce tendency of reaction with carbonyl compounds.Moreover,this methodnot only enhances the dispersibility,but also keeps graphene plane intact.Followed experiments reveal that graphene aqueous dispersion has an extraordinary dispersibility,while diluting this dispersion with other polar solvent.(3)Reduction reaction of mentioned graphene aqueous dispersion was accomplished via thermal treatment.According to the comparison of the characterizationresults of Raman,UV,IR and other characterization of the initial product and the reduction product,which further verified the mechanism of the ball milling reaction proposed in this paper.Subsequently,resistance of sheet,filmed by suction filtration of graphene dispersion,is measured,and the outcome unveils that graphene manages to recover the originally electrical properties.This shows that in this experiment,not only produced a high quality graphene aqueous dispersion,but also preserve its excellent performance,so that its performance is not affected after the reduction.This is very important for the application of graphene materials in practical fields.