Study On Preparation And Properties Of Eucommia Ulmoides Gum Electromagnetic Shielding Composites

With the development of polymer materials,electromagnetic shielding rubber composites have gradually become efficient electromagnetic interference(EMI)shielding materials due to their high elasticity,low density and good sealing property.So far,a mass of rubbers have been studied for EMI shielding rubber composites,but there are few reports about eucommia ulmoides gum(EUG)as matrix of EMI shielding rubber composites.EUG is a natural polymer material with crystalline structure,an isomer of natural rubber(NR),it shows advantages of low heat generation,wear resistance,water resistance,acid and alkali resistance and shape memory,which make the EMI shielding rubber composites designed with EUG as the matrix can be applied in practical production and life.In this thesis,using EUG as the matrix,and nickel-plated graphite(NCG),graphene nanoplatelets(GNPs)and carbon nanotubes/graphene nanoplatelets(CNTs/GNPs)as EMI shielding functional fillers respectively,EUG based EMI shielding rubber composites with high electrical conductivity and EMI shielding properties were prepared.EUG/NCG composites and NR/NCG composites were prepared by mechanical blending with the same content of NCG as the EMI shielding functional filler.The results showed that EUG/NCG composites showed more excellent electrical conductivity and EMI shielding property than NR/NCG composites,it was proved that the crystal structure of EUG can help to improve the electrical conductivity and EMI shielding properties of composites.EUG/NCG composites were prepared by mechanical blending.The results showed that continuous NCG conductive network structure were realized in the EUG matrix.With the increase of NCG content,the electrical conductivity and EMI shielding properties of the EUG/NCG composites were enhanced.When the NCG content was 50wt%,the EUG/NCG composites presented optimal electrical conductivity of 2.59S/cm and EMI effectiveness(EMI SE)of 47.50 d B.EUG/NCG composites still retained crystal properties and had good mechanical properties.EUG/GNPs composites were prepared by solution blending and molding.The results showed that the adjunction of GNPs made the crystals form of EUG change from beta-form crystals to alpha-form crystals.With the increase of GNPs content,the electrical conductivity and EMI shielding properties of EUG/GNPs composites were obviously enhanced.When the GNPs content was 20wt%,the EUG/GNPs composites presented optimal electrical conductivity of 1.53S/cm and EMI SE of 37.14 d B.CNTs and GNPs were dispersed in the EUG matrix at the same time,EUG/CNTs/GNPs composites were prepared by the method of solution blending and mechanical blending.The results showed that the EUG/CNTs/GNPs composites behaved excellent electrical conductivity and EMI shielding properties because of the existence of CNTs/GNPs 3D network structure.When the CNTs content was 9.62wt%,and the GNPs content was 3.85wt%,the EUG/CNTs/GNPs composites presented optimal electrical conductivity of 2.71S/cm and EMI SE of 42.49 d B,superior to most of the reported rubber composites.In addition,EUG/CNTs/GNPs composites also had excellent mechanical properties and good thermal stability.