Modification Of Graphene Oxide And Preparation And Properties Of Modified Graphene Oxide/epoxy Resin Composites

In recent years, the dispersion of graphene oxide into polymer matric at nanoscale hasreceived wide attention. Compared with conventional materials, the nano material possessesincomparable advantages on the performance, which generally depends on the degree ofdispersion of nano fillers into the polymer matric. However, due to the strong hydrophiliaand weak lipophilicity, it is difficult for graphite oxide to acquire stable dispersion andseparation from the majority of organic solvents, limiting its application to the compositematerials. Therefore, the modification and functionalization on surface of graphene oxideare of great importance to promote the performance of graphene oxide nano compositematerial.In this paper, three methods in the preparation of graphite oxide were investigated (GO)in order to seek out a method with simple operation and non-pollution. The surfacemodification and functionalization of graphene oxide was carried out through introducingcoupling reagent and Zn2+. And various epoxy nanocomposites were obtained. Thenanocomposites were characterized by XRD, SEM, TG, EDS, UV, FTIR. Meanwhile, theirperformance was compared with respect to mechanical properties, thermostabilization andwater absorption. Main results are shown as follow:(1) Three methods, including Hummers method(HGO), Improved Hummersmethod(IGO) and Solvothermal method(SGO), were all qualified in the preparation of GOwith similar morphology and structure. However, the degree of oxidation did differ fromeach other, which was in the following sequence: SGO>IGO>HGO. Specially, HGOretained much more aromatic structure. In contrast, the preparation process of IGO and SGOpossessed several advantages in comparison to conventional Hummers method, such assimple operation, non-pollution and practical for use.(2) KH550, KH560and KH570were all successfully grafted onto the graphene oxide,and KH570appeared to be optimal coupling reagent with remarkable promotion inlipophilicity. The results from our study showed that the optimized dosage of KH570/GOwas0.05wt%, and while it was added into epoxy nanocomposite, the tensile strength, tensilemodulus, ultimate elongation and impact strength reached the maximum, which increasedby104.32%,14.46%,118.89%and89.84%, respectively. At the same time, the waterabsorption rate of the nanocomposite decreased by44%with slihhtly increase inthermostability of the high temperature phase, suggesting that the dispersion of modified GO played a key role in the performance of the composite.(3) The nano ZnO particle, which could be uniformly loaded on the slice of GO, leadto decrease in hydrophilicity and increase in thermostability. It is found that the optimalratio of ZnO/GO was0.25wt%. When it was added to the epoxy composites, the mechanicalproperties of this composite reach optimum. In comparison to the original composite, thetensile strength, tensile modulus, ultimate elongation and impact strength increased by99.87%,12.09%,98.35%,151.48%, respectively. Meanwhile, the water absorption rate wassignificantly reduced by81.48%and the thermostability of the temperature phase wasslightly improved. These results indicated that the ZnO loaded on GO had preferablecompatiblity and interface bonding force with epoxy resin matrix.