Preparation And Properties Of The Modified Graphene And Their Rubber Composites

In this paper,nitrogen-doped graphene(NG)was prepared by a one-step radical exfoliation method and used as a natural rubber(NR)filler to successfully prepare NG/NR composites.The effects of NG addition on the tensile properties and thermal stability of the composites were systematically discussed.Nitrogen-doped graphene was modified with 2-acrylamide-2methylpropanesulfonic acid(AMPS)as modifier.Natural rubber composites were prepared with modified nitrogen-doped graphene(AMPS-NG)as filler,and the effects of modified nitrogen-doped graphene addition on the tensile properties and thermal stability of the composites were discussed.The main research contents and results are summarized as follows:(1)Preparation and Characterization of Nitrogen-Doped Graphene.Using aspartic acid as exfoliation aid and nitrogen source,nitrogen-doped graphene was prepared from graphite by radical exfoliation method.The prepared nitrogen doping was characterized by Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD),Raman spectroscopy(Raman Spectrum),X-ray photoelectron spectroscopy(XPS)and elemental analyzer(EA).Graphene samples were analyzed.Single factor experiments were used to investigate the effects of dispersant dosage,nitrogen source dosage,current intensity and reaction time on the preparation process of nitrogen-doped graphene.Nitrogen-doped graphene with a nitrogen content of up to 5.13% was obtained.(2)Preparation and Properties of NG/NR Composites.NG/NR composites were prepared by mechanical blending method.The morphologies were analyzed by scanning electron microscope(SEM),the thermal stability of the composites was analyzed by thermogravimetric(TG),and the tensile properties of the samples were evaluated by a universal testing machine.The results show that the thermal stability and mechanical properties of NG/NR composites are significantly improved over NR.When 0.4 parts of NG was added,the results showed that compared with NR,the thermal decomposition temperature of NG/NR composites increased by 29.5 °C,the maximum load increased by91.23%,the elongation at break increased by 15.98%,and the tensile strength increased by140.54%.(3)Preparation and characterization of AMPS-modified nitrogen-doped graphene.AMPS was used as modifier to prepare modified nitrogen-doped graphene(AMPS-NG).The structure of the as-prepared AMPS-NG was analyzed by means of FT-IR,XRD,Raman Spectra,XPS and EA.The response surface analysis model was established using Design Expert 12.0 software.The preparation process conditions of AMPS-modified nitrogendoped graphene were optimized: NG 0.60 g,AMPS 1.10 g,the reaction temperature was76 °C,and the reaction time was 3.5 h.The product sulfur content was 4.35%.(4)Preparation and Properties of AMPS-NG/NR Composites.AMPS-NG/NR composites were prepared by mechanical blending method.The thermal stability of the composites was analyzed by TG,and the tensile properties of the samples were evaluated by a universal testing machine.The results show that,compared with pure NR,when 0.4 phr of AMPS-NG is added,the thermal decomposition temperature of AMPS-NG/NR composites increases by 45.6 °C,the maximum load increases by 182.74%,the elongation at break increases by 43.5%,and the tensile strength increases.Strength increased by 162.16%.