| With the development of the intelligent 5 G era,advanced electronic and electrical equipment has brought people an efficient and convenient life,but the accompanying electromagnetic radiation and interference cannot be ignored.At present,electromagnetic shielding is one of the effective measures to solve electromagnetic radiation pollution,and the development of high-performance electromagnetic shielding materials has become a research hotspot in recent years.Epoxy resin（EP）has the characteristics of good adhesion and good mechanical properties,and its room temperature curing process requires simple equipment and low cost.This article uses4,4’-diaminodiphenylmethane（DDM）and acrylic acid（HAA）to produce acrylamide as the curing agent for epoxy resin（E-51）,and uses carbon fiber（CF）,nickel-plated carbon fiber（NiCF）,carbonyl iron powder（CIP）,ferroferric oxide（Fe3O4）or fiber/particle composite fillers are used as the reinforcing phase and electromagnetic shielding filler.Fiber and fiber/particle reinforced epoxy resin composite materials are prepared,and their curing behavior,electromagnetic（EMI）Shielding performance,thermal performance,mechanical performance and fracture morphology have been studied.Two composite materials of EP/CF and EP/NiCF were obtained by curing at room temperature,and the effects of fiber length and addition amount on the curing behavior and performance of EP were studied.Influence.Compared with pure EP,the EMI shielding performance（SE）,thermal performance and mechanical properties of the composite material are significantly improved after the fiber is added,and the fiber with a length of 3 mm has better performance than that of 1 mm.When the fiber content is12 wt%,the EMI shielding performance and thermal performance of EP/CF-3 mm and EP/NiCF-3 mm composites are the best,with SE of 38.2 d B and 42.2 d B,respectively,which are 17.2 times and 19.1 times higher than pure EP,respectively;T5increased by121℃and 110℃ respectively.When the fiber addition amount is 4 wt%,the mechanical properties of EP/CF-3 mm and EP/NiCF-3 mm composites reach their peak,and the tensile strength,flexural strength and impact strength of the two are increased by 17%and 16%,36%and 34%,158%and 151%respectively.Four room temperature curing composite materials,EP/CF/CIP,EP/NiCF/CIP,EP/CF/Fe3O4 and EP/NiCF/Fe3O4,were further prepared,and the effect of the content of iron-based magnetic particles CIP or Fe3O4 on their performance was studied.The test results show that with the increase of magnetic particle content,the shielding performance and thermal stability of the system are improved,but the mechanical properties show a trend of increasing and then decreasing,and the enhancement of Fe3O4 is better than CIP for the material properties.when the Fe3O4 addition amount is35 wt%,EP/CF/Fe3O4 shows the best comprehensive performance,and its EIM shielding performance reaches 44.5 d B,T5 increased to 260°C,and the bending strength and impact strength were 122.4 MPa and 42.2 k J/m2,respectively. |
