| Epoxy resin has the characteristics of low curing shrinkage,good manufacturability,good stability,excellent bonding performance,etc.,but its toughness is poor,its impact resistance is weak,and it has electrical insulation.As an emerging carbonaceous material,graphene has excellent charge transport properties,high thermal conductivity,and excellent mechanical properties,which can improve the toughness and electrical insulation properties of epoxy resins.Therefore,in this paper,the two are combined,graphene as the filler,epoxy resin as the matrix,and graphene/epoxy resin composite materials are prepared by using methylhexahydrophthalic anhydride and 4,4-diaminodiphenylmethane as curing agents.And the electrical properties,electromagnetic shielding effectiveness,mechanical properties and thermal stability of the composite materials were studied.Research indicates:(1)Compared with pure epoxy resin,the impact strength of the composite material with methylhexahydrophthalic anhydride as the curing agent increases with the increase of graphene content and reaches 1.59 kJ/m~2 when the graphene content is7.5 wt%.The bending strength showed a downward trend.From the thermogravimetric analysis results,it can be seen that when the graphene content of the composite material gradually increases,the temperature of 10%weight loss has decreased,while the temperature of 50%weight loss is basically unchanged.SEM pictures show that with the increase of graphene content,graphene is gradually dispersed in epoxy resin to form a conductive network,which significantly improves the conductivity and electromagnetic shielding efficiency,respectively 2.38×10~-33 S/m and 3.87 dB.(2)With the increase of graphene content,the composite materials prepared with4,4-diaminodiphenylmethane as the curing agent have significantly improved impact strength,reaching 1.67 kJ/m~2when the graphene content is 7.5 wt%.The electrical conductivity and electromagnetic shielding effectiveness of the composite material also increased significantly with the increase of graphene content,respectively1.34×10~-33 S/m and 2.96 dB.Bending strength and fracture toughness showed a downward trend.The electrical conductivity and electromagnetic shielding effectiveness of composite materials also increased significantly with the increase of graphene content.Bending strength and fracture toughness showed a downward trend.Studies have shown that graphene/epoxy composites cured with two curing agents have significantly improved impact resistance,electrical conductivity,and electromagnetic shielding effectiveness,improving the toughness and electrical insulation of epoxy resins. |
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