Study On The Preparation Of Graphene Composites From Graphite

This paper proposes a new method for the direct preparation of graphene composites from graphite by in-situ ball-milling-polymerization.Based on the principle of mechanochemical chemistry,in-situ exfoliation of graphite by ball milling in a polymer monomer solution results the conversion of graphite to graphene,and The graphene is evenly dispersed in monomer solution of the polymer by ultrasound,and then the graphene polymer composite material is obtained by the polymerization.With this method,composites of polystyrene,epoxy resin with graphene were successfully prepared.The evaluation of the mechanical properties and thermal conductivity of the composites was performed.Wet exfoliation of graphite by in-situ milling.By changing the rotational speed of the star ball mill,ball milling time,and the ratio of graphite to monomer,a dispersion solution of graphene、graphite and monomer is obtained,the structural analysis shows that graphene is composed of a single layer and a few graphenes.It was redispersed in monomer solution with ultrasound.Bulk polymerization was used to prepare the graphene/polystyrene composite material with azobisisobutyronitrile as initiator,ethylene glycol as the dispenserGraphite is ball-milled and exfoliated to graphene in epoxy resin acetone solution,and obtianed an epoxy resin–graphene dispersion,it was solidifized by diethylenetriamine curing agent to obtain a graphene/epoxy resin composite.Experimental results confirmed that the thermal conductivity and mechanical properties of the polymer matrix composites obtained in this study are significantly higher than that of their pure polymers;the thermal conductivity of Graphene/PS composite is increased by 20 times compared to that of its pure polystyrene.The modulus of the Graphenen/EP composites can reach 3750.0 MPa,the tensile strength is 50.0 MPa,and the bending strength of the Graphene/EP composites is 89.0 MPa,which is 41.0%,20.0%,and23.6% higher than that of the pure epoxy resin,respectively.The developped preparation method and process can provide important and practical reference for the preparation of other graphene-polymer composites.