Study On Graphene By "One Step Reduction Modification" And Its Composites

As a new two-dimensional nano carbon material,graphene has unique crystal structure,an excellent physical and chemical property,which has broad application prospects in various fields such as materials and electronics.Nevertheless,due to the high specific surface area structure and strong?-?interaction,graphene presents irreversible stacking,which is easy to aggregate in solvent,resulting in poor dispersion.At the same time,the lack of active functional groups on the surface limits the application of graphene in composites.Therefore,it is an effective method to prepare graphene composites by surface modification of graphene to retain its excellent properties and improve its compatibility with polymers.In this paper,functional graphene with good dispersion was prepared by"one-step reduction modification",and the interfacial interaction between graphene and polymer was improved by chemical grafting.The specific research contents and results are as follows:(1)Graphene oxide(GO)was prepared by modified Hummers method.Diethylene glycol was used as reducing agent and modifying agent to achieve"one-step reduction modification"of graphene oxide.Then the ring opening polymerization of caprolactone was initiated by the surface active hydroxyl group of graphene.The products were characterized by Fourier transform infrared spectroscopy and transmission electron microscopy.The graft product(PCLG)exhibits good and stable dispersion in organic solvents,which lays a foundation for the formation of composite materials between graphene and polymer.(2)The PCLG and biopolymer polylactic acid(PLLA)matrix were obtained by solution blending to prepare composite materials,and the influence of blending ratio on the thermal properties,mechanical properties and other properties of the composite materials was investigated.The results showed that PCLG can be uniformly dispersed in the PLLA matrix,which promotes the crystallization behavior of polylactic acid.When the blending ratio of PCLG and PLLA was 1 wt%,the composite material not only showes good hydrophilicity and electrical conductivity,but also has significantly improved mechanical properties and thermal stability compared with pure PLLA.(3)While GO was reduced and modified here,Fe₃O₄nanoparticles were grown on the surface of the graphene to prepare magnetic graphene,and the surface was grafted with caprolactone(PCLFG).Nanomaterials not only have good magnetic properties,but also exhibit good dispersibility in organic solvents.This method can also load metal oxides on graphene.(4)PCLFG and PLLA were blended to prepare composite materials and the effects of different blending ratios on the composites were investigated.The addition of Fe₃O₄nanoparticles promotes the thermal degradation of PLLA matrix.When the blending ratio of PCLFG is 5 wt%,the composite exhibites good mechanical properties and magnetic properties.