Study Of Lightweighting And Electromagnetic Properties Of Graphene Nanoplates/Porous Polyethersulfone Matrix Composites

Polymer matrix composites have many advantages such as excellent mechanical performance and heat resistance,have been widely used in important fields such as aerospace and military.However,with the continuous upgrading and improvement of modern aerospace and military equipment,lightweight and functional polymer matrix composite materials have shown great application value.Currently,lightweight polymer matrix functional composite materials are mainly based on lightweight and insulating polyurethane foam.However,these materials have poor mechanical performance,heat resistance,and flame retardancy.Therefore,there is a need to find a porous polymer matrix material to replace polyurethane foam to achieve lightweight,high specific strength and modulus,as well as excellent insulation,flame retardancy,and electromagnetic properties.Polyethersulfone is a good candidate for replacing polyurethane foam to manufacture lightweight and functionally good matrix materials because of its excellent mechanical performance,heat resistance,and flame retardancy,and its ability to form various structural features of porous materials.The porous structure can give polyethersulfone matrix composite materials lightweight,insulation,and flame retardancy properties.In order to further obtain the conductivity and functionality of porous polyethersulfone on the basis of lightweight,this study added graphene nanoplates with excellent conductivity to form a wall-connected porous conductive network in polyether sulfone,making the graphene nanoplates/porous polyethersulfone composite material have excellent conductivity and heat resistance.At the same time,with the addition of a small amount of graphene nanoplates,the three-dimensional porous conductive network can achieve good electromagnetic performance.In addition,due to the insufficient mechanical performance of the graphene nanoplates/porous polyethersulfone material,this study imitated the microstructure of bamboo and used carbon fiber as a reinforcement and graphene nanoplates/porous polyethersulfone as a matrix to produce a lightweight,high specific strength and modulus bamboo-like carbon fiber functional composite material,and carbon fiber has good conductivity,which can give the bamboo-like carbon fiber functional material electromagnetic shielding properties.(1)By introducing the porous structure through phase transformation,graphene nanoplates are present within the porous polyethersulfone pore walls,and only a very small amount of graphene nanoplates can be used to form an effective conductive network within the pore walls.The construction of the conductive network allows the graphene nanoplates/porous polyethersulfone film to have excellent conductive properties.In addition,the porous structure gives the graphene nanoplates/porous polyethersulfone film excellent thermal insulation and heat retention properties.(2)The three-dimensional conductive network formed by the graphene nanoplates in the porous polyethersulfone matrix not only provides a pathway for the transport of electrons in the graphene nanoplates/porous polyethersulfone,but also enhances the reflection and scattering effects of electromagnetic waves.At the same time,the good electrical conductivity gives the graphene nanoplates/porous polyethersulfone composite excellent microwave absorption properties.The graphene nanoplates/porous polyethersulfone composite achieves a minimum reflection loss of-50.90 d B at 10.99 GHz and an effective absorption bandwidth of 1.59 GHz.(3)By imitating the microstructure of bamboo,the graphene nanoplates/porous polyethersulfone is made to significantly improve its mechanical properties while maintaining its light weight.At 1.25 vol%of graphene nanoplates,the tensile specific strength of the bamboo-like lightweight carbon fibre functional composite is 4.59×10~5 m~2/s~2 and the tensile specific modulus is 1.69×10~6 m~2/s~2.The electromagnetic shielding properties of the bamboo-like lightweight carbon fibre functional composite are enhanced as the graphene nanoplates content increases.When the graphene nanoplates content is 5 vol%,the shielding effect of the bamboo-like lightweight carbon fibre functional composite is 19.07 dB.