Preparation And Properties Of Graphene/Silicone Rubber Conductive Composites

Silicone rubber composites with low density,high elasticity and wide band shielding have potential application value in the field of electromagnetic shielding.Based on this,the methyl vinyl silicone rubber with excellent heat and cold resistance,vulcanization performance and compression permanent deformation resistance was used as the matrix material in this research.The following aspects were mainly studied in this paper:The effects of the type and amount of graphene,the type and amount of coupling agent and the preparation process of the composites on the electrical conductivity of graphene/silicone rubber conductive composites were studied.The results show that the conductive percolation value of graphene/silicone rubber conductive composites is 4.2vol%,and Its volume resistivity can be as low as 1?10?·cm.It is difficult to obtain high conductivity rubber with volume conductivity higher than 1 S/cm by filling graphene filler alone.which cannot meet the requirements of electromagnetic shielding efficiency(?60 dB)(200 kHz?15 GHz).The effects of doping graphene with silver coated aluminum powder on the mechanical and electrical properties of the composites were studied.The results show that the conductivity of graphene QD-GE1(300?400S/cm)is much lower than that of silver coated aluminum powder(>104S/cm).When graphene is used in silver coated aluminum powder/silicone rubber composites,which hinders the direct contact of silver coated aluminum powder with high conductivity.It is disadvantageous to the conductivity and electromagnetic shielding performance of the composites.By investigating the influence of doping silver coated graphene with silver coated aluminum powder on the properties of composite materials,it was found that silver coated aluminum powder(120phr)/silver coated graphene(10phr)/silicone rubber composite materials can meet the target of the subject.By studying the effect of doping silver coated graphene with granular and fibrous conductive fillers on the mechanical and electrical properties of the composites,it was found that doping of fillers with different shape coefficients could improve the mechanical and electrical properties of the composites.The optimum doping ratio was silver coated aluminum powder:silver coated graphene:silver coated glass fiber(20%)=136:5:24.But this kind of promotion is not significant and cannot achieve the desired effect.