Functional Modification Of Graphene And Application Of Composite Materials

The unique monatomic structure of graphene(GE)determines its unique properties,such as extremely high strength,extremely high thermal and electrical conductivity,extremely large specific surface area,and high barrier.Such a material would revolutionize many industries and technologies.The experiment focused on the preparation,modification and application of graphene in composite materials.In the first part,we studied the preparation of graphene and new modified graphene: grafted long alkyl chains on the surface of graphene stripped by tannin(TA)assisted liquid phase,and compared the effects of modified graphene on the properties of natural rubber composites.Firstly,TA was used as a dispersing agent for liquid-phase graphene stripping to prepare stable and high-quality graphene(TGE).Subsequently,the active sites of tannins were grafted with octadecanamide by mannich reaction to obtain NTGE.The results showed that NTGE had better reinforcing effect than TGE.Adding 1 portion of NTGE,the tensile strength and tearing strength were the best,which were 33% and 20% higher than pure NR,and 9% and 4% higher than TGE rubber composites,respectively.The wear resistance of natural rubber composites with 1.5 NTGE was 27% higher than that of pure NR.The second part studied a new type of graphite alkenyl ammonium polyphosphate(APP)of flame retardant: preparation of graphene based TA-Fe(?)complex capsules flame retardant ammonium polyphosphate association effect,and research the new flame retardants on the mechanical and flame retardant properties of natural rubber.Experiment based on the tannic acid(TA),physical adsorption on the surface of the APP and graphene,and TA and Fe(?)chelation,get a TA-Fe(?)complex capsules APP,and realizes the APP and GE together,get a graphene based TA-Fe(?)complex capsules,ammonium polyphosphate flame retardants(MGAPP).The effects of APP before and after encapsulation on the mechanical and flame retardant properties of natural rubber composites were compared.The results showed that MGAPP/NR showed better flame retardant effect than APP/NR,with LOI reaching 27%,ul-94 reaching v-1 level,significantly increased carbonization amount,MGAPP/NR had the lowest pHRR and the lowest THR value.The more prominent advantage is that the tensile and tearing strength of MGAPP/NR is significantly higher than that of pure NR,by 18% and 17% respectively,while the mechanical properties of APP/NR are significantly reduced,indicating that MGAPP improves the compatibility between APP and natural rubber.In the third part,a new type of go 9,10-dihydrogen-9-oxo-10-phosphorus-phenanthrene-10-oxide(DOPO)synergetic flame retardant was studied.DOPO(KDOPO)was prepared by coupling agent modification of DOPO by mannich reaction between KH550 and DOPO.Then DGO was combined with phenolic epoxy resin to form a flame retardant coating,which was applied on the surface of foamed EPS board to obtain flame retardant EPS board.The results showed that compared with pure EPS and DOPO/EPS foam board,DGO/EPS presented better flame retardant performance.The LOI value of 20 g DGO/EPS increased to 29%,reaching v-0 rating,and there was no melting drop.The pure EPS pHRR and THR were significantly reduced,and the smoke suppression effect was significant.