Study On The Properties Of Graphene/polyurethane Composites Based On Random Dispersion Representative Volume Element

Since highly developed software emerged rapidly,simulation methods have been widely used among materials field,which can predict materials parameters.During the simulation process of polymer-based conductive composites,the distribution of conductive fillers determines the simulation results,while most of the current studies fixed their distribution,resulting in underfitting results.In order to solve this,this paper established a representative volume element model of graphene/polyurethane composites,where graphene was completely randomly distributed,and its electrical and mechanical properties were calculated.According to the microscopic response cloud map,the enhancing mechanism of graphene composites is analysed.Firstly,the graphene/polyurethane composites were prepared through solution blending method,followed with characterisation,by which the size,structure and distribution of nano-fillers were determined.Based on this,the model and parameters of graphene were built through DIGIMAT platform,using approximate platelet model was used to represent graphene,and a representative volume element(RVE)model was established,in which the graphene sheets are completely randomly distributed.Secondly,according to the mechanical and electrical strengthening mechanism of graphene(infiltration,tunnelling equivalence),the interface parameters of the model are set to simulate the properties.Finally,through the obtained mechanical and electrical response cloud map,the graphene strengthening mode and mechanism are analysed.In addition,taking advantages from the mechanical data in the simulation,the ABAQUS software is used to simulate the stress trends of the material.The results show that compared with the polyurethane,the electrical and mechanical properties of the composite are significantly improved,by overall resistivity reduced 4 magnitude orders to 108 Ω·cm;elastic modulus increase 18.4%to 41.04MPa,when the graphene content reaches lwt%.After comparison,it is found that the test results basically consistent with the RVE simulation results,while the model using interfaced-disk graphene has a smaller error,indicating when calculating overall conductivity of the polymer-based composites,it is necessary to consider the interface parameters between filler and matrix.Combining RVE with ABAQUS to realise analysis calculations,the stress distribution of the composite material was successfully simulated.It shows that the use of RVE model combined with other finite element software can carry out more accurate simulation of composite materials with different structures.This paper use RVE simulation method carried out mechanical and electrical properties analysis of graphene/polyurethane composites,and the formation of conductive network and mechanically strengthened network is studied,which has important reference value for the performance prediction of polymer-based graphene composites,as well as providing a basis for the application of simulation to guide specific experiments.