Study On Preparation And Properties Of Structural Wave Absorbing Composite Materials Via VARI Process

Structural absorbing material has become one of the important research fields for its excellent mechanical property,wave absorbing property and designability.In order to obtain the structural absorbing material with excellent wave absorbing property,a large number of wave absorbing agents are usually added into the composites,but the mechanical property of the composites are easily damaged by the wave absorbing agents.It is a key problem to be solved in the development of structural absorbing material,which reduces the damage to mechanical property caused by wave absorbing agents.In order to solve this problem,a new vacuum assisted molding process(VARI)was chosen as the main forming method in this paper.The preparation and properties of carbonyl iron powder/glass fiber/carbon fiber/epoxy resin(CIP/GF/CF/EP)laminated plate structural absorbing material were studied.Firstly,PAM-RTM was used to simulate the filling process of VARI in this paper.The influence of resin viscosity,vacuum degree and resin injection mode on the filling process were studied.The results indicated that: resin filling time is the shortest when the viscosity is the lowest,the vacuum pressure is the largest,and the resin injection mode is the linear injection;When the vacuum pressure is 0.09 MPa and the injection mode is linear,the simulated filling time of four resin systems with CIP:EP mass ratio of 0:1?0.5:1?1:1?and 1.5:1 at 35? is 33.4s?34.8 s?39.4s and 47 s,respectively.Secondly,CIP/GF/CF/EP structural composites were prepared by VARI based on the best process parameters by simulation.The effects of different CIP content on the microstructure,thermal property,mechanical property and wave absorbing property of the composites were studied.The results indicated that: the mechanical property of structural composite could be enhanced by adding appropriate CIP content.When the mass ratio of CIP:EP is 1:1,the mechanical property and wave absorbing property of CIP/GF/CF/EP composite matched well.The maximum reflection loss value was-14.32 dB in 12.32 GHz,the bandwidth was 2.6 GHz,and the tensile strength was 314.4 MPa.The bending strength was 282.2MPa.the compressive strength was 234.1MPa.the interlaminar shear strength was 29.5MPa.Finally,the surface of CIP was modified by silane coupling agent and epoxy sizing agent and the composite material was prepared,respectively.The effects of surface modification of CIP on the microstructure,thermal property,mechanical property and wave absorbing property of composites and their optimization mechanism were studied.The results indicated that: the surface modification of CIP could improve the oxidation resistance of CIP and the interfacial compatibility and strength of CIP and epoxy resin.Two modified CIP/GF/CF/EP composites exhibited excellent mechanical property and wave absorbing property,and were superior to the unmodified CIP/GF/CF/EP composite.It is a kind of structural absorbing material with practical application value.