Studies On Electrical And Thermal Conductivity Of Graphene Composites

Graphene has been widely used as functional filler in polymer matrix due to its excellent properties.However,graphene is difficult to dissolve in polymer matrix,so it is crucial to prepare graphene with high solubility,which is beneficial to increase the utilization rate of graphene,but also less costly of materials prepared.In this paper,electrical and thermal conductive composite is prepared by graphene and EPDM,which can achieve high-strain.Based on the above reasons,the preparation of soluble graphene should be performed.The graphene used in this paper is prepared by thermal expansion method and temperature-controlled ultrasound technology,which makes the cost lower and the solubility better,and is conducive to the performance of subsequent materials.Because of its excellent solubility,the dispersion of graphene in EPDM was improved.The GnPs/EPDM mixture exhibited relatively low percolation threshold of 2.9wt%,which is lower than that in many literatures.Thermal conductivity of the composite reaches 0.72W/m.k at 7wt%,meanwhile,with the increase of graphene content,the thermal stability of the composites increase gradually.According to the electrical of the composites,the sensing properties of graphene/EPDM composites were studied.The graphene/EPDM composites with graphene content of 3 wt% and 5 wt% were tested by various mechanical tests.The monotonic tensile test results show that the sensor with graphene content of 3wt% has a high sensing coefficient of 129.33.When graphene content is 5 wt%,the linear growth of the electrical response is softened.There are two different sensitive stages of linear change:0-210% and 210-300%,and the sensing coefficients are 52.76 and 107.99,respectively.The strain sensor mechanism is also discussed.Cyclic loading-unloading tests show that the composite has good stability and repeatability,and can monitor elbow and finger bending behavior.High performance graphene/EPDM composites have excellent thermal and electrical conductivity,and show promising application in the field of sensors.