Research On The Effect Of Carbon Nanotubes And Graphene Oxide On The Properties Of Epoxy Resin Composites

When epoxy resin(EP)are mixed with curing agent and solidified to produce a three-dimensional network cross-linked structure,its mechanical properties will be greatly improved,resulting in extremely high utility value.However,it still has the disadvantages of being brittle and having low strength.Carbon nanotubes(CNTs)and graphene are generally considered to be good reinforcing materials and can be added to the polymer matrix for modification.On the one hand,due to the relatively strong molecular interaction between CNTs,they tend to agglomerate,resulting in weaker dispersion.On the other hand,since the surface activity of the CNTs is small,the binding force between the CNTs and the EP is very low.In order to solve the problem of easy reunion of CNTs and its low binding force with the EP interface,the MWCNTs were grafted with active amine groups to modify MWCNTs in a covalent functional manner.Firstly,the original MWCNTs were treated with acid,and the surface was grafted with hydrophilic groups that were easy to react with amino groups.Then carboxyl functionalized and amine functionalized MWCNTs were prepared,and the prepared samples were characterized by various methods,showing very good dispersion and stability.The MWCNTs/EP composites were prepared by mechanical blending.The influence of different loads on the friction and wear properties of the composites was studied by using a M-2000 friction and wear machine.The effect of the amount of MWCNTs added,the amount of functional groups of modified MWCNTs and MWCNTs on the friction and wear properties of the composites were studied.When the content of carboxylated MWCNTs was 0.5 wt%,the friction coefficient was reduced by 44.91%compared to the pure EP.The wear rate was reduced by 96.29%,which greatly improved the wear resistance of composite materials and the wear mechanism was analyzed.A mechanical mixing method was also used in this paper to prepare composites by uniformly mixing GO and MWCNTs with EP and curing agent.The tensile and bending properties of the composites were studied.The tensile and bending properties of the composites were investigated by the different ratios of graphene and MWCNTs.The results showed that GO and MWCNTs could indeed improve the tensile and bending properties of EP composites;GO improves the tensile properties of composites better than MWCNTs,when the content of MWCNTs was 0.1 wt%,the tensile strength of the composite increased by 26%,and when the GO was 0.1 wt%,the tensile strength increased by 60%;MWCNTs improve the bending properties of composites better than GO,when the content of MWCNTs was 0.1 wt%,the flexural strength and flexural modulus of the composites increased by 78%and 124%respectively.The existence of carboxyl functional groups on the surface of GO and MWCNTs helps to improve their dispersibility in EP composites,thereby improving the wear resistance and mechanical properties of composites.The more surface carboxyl groups,the better the effect in improving the mechanical properties of the composite materials.