| In this paper, we used epoxy resin as the matrix. In order to improve the strengh and toughness properties, we used the graphene oxide(GO) and GO-MWCNTs(carbon nanotubes) to modify epoxy resin. The mechanical properties, thermal performance and other properties were studied. Meanwhile, the curing kinetics of GO-MWCNTs nano materials were studied. The study results were as follow:Firstly, Graphene oxide(GO) was prepared from improved expandable graphite by hydrothermal process and ultrasonication. The structures of the graphene oxide were characterized by XRD,AFM and FT-IR. Then,the graphene oxides were extracted to the epoxy resin matrix through two-phase extraction methods. The structures and fracture morphologies of composites were investigated. And the mechanical properties and DMA were also characterized.GO on the enhancement mechanism of the epoxy resin were analyzed.the results indicate that the GO is well dispersed in the epoxy resin. And the mechanical properties of composite material compared with pure epoxy have significantly improved. When the amount of GO is 0.25 wt%, the impact strength of composite is maximum, which increases by 115 %.At the moment, the elongation at break increases by 78 %.The toughness of the epoxy resin greatly increases.Secondly, Graphene oxide(GO) was prepared from improved expandable graphite by hydrothermal process and ultrasonication. Then, the graphene oxides were extracted to the epoxy resin matrix through two-phase extraction methods. And the MWCNTs were spreaded in the MHHPA by the ultrasonic dispersion and the thermal catalytic reaction. The fracture morphologies of the GO-MWCNTs/EP composites were investigated by SEM. And the mechanical properties and DMA were also characterized. The results indicate that the properties of the material have significantly improved both in the mechanical properties and the thermal stability compared with pure epoxy. When the amount of the GO is 0.1 wt% and the MWCNTs' is 0.4 wt%, the impact strength of the composite is maximum. The intensity value is 84.22 KJ/m2, which increases by 137 %. At the moment, the tensile strength also increases,as well as the the elongation at break, The former increases by 48.4 %, and the latter is 97.9 %. The above datas show that GO-MWCNTs has synergistic enhancement effect and synergistic toughening effect on epoxy resin.Finally, in this paper, with the graphene oxide modified epoxy resin, curing agent modified by hydroxylation carbon nanotubes, the modified curing agent and the modified epoxy resin will be mixed evenly. Adding promoter(for curing) to get composite samples. Scanning the sample and pure epoxy system by non-isothermal DSC method to get the DSC curve, then analyze the DSC curve. First, use the model fitting method(Friedman method) to get activation energy and the former factor of the epoxy system which is needed for the model fitting. Then using the curing kinetics equation which is obtained from the model fitting methods, E and logA of Friedman method will be served as the initial conditions of regression calculation for nonlinear fitting, to get pure resin system n-tier model fitting kinetic parameters and modified epoxy system Kamal model fitting kinetic parameters. Learning the starting temperature, peak temperature and ending temperature of different heating rate with linear regression analysis, extrapolating the initial curing temperature and peak temperature of the heating rate of 0, to determine the best scope of the curing temperature of epoxy resin system. Finally compare the DSC experiment curves with the calculated DSC curve of model fitting and to verify the rationality of reaction model. Then test the isothermal curing kinetics and model fitting of pure epoxy resin and nanocomposites. And the fitting values were compared to the experimental value, which can verify the rationality of the reaction model. |
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