Preparation And Analysis Of Foam Conductive Adhesive For Electromagnetic Shielding

With the advent of the information age,human beings have entered the Internet era.Mobile Internet devices such as mobile phones and tablets have entered every corner of people’s lives,bringing great convenience to human life.However,at the same time,these devices also produce electromagnetic radiation,bringing harm to environmental radiation and laying hidden dangers for signal safety.Therefore,electromagnetic shielding technology has attracted more and more researchers’attention.Especially in the era of 5G with high frequency and high speed,electromagnetic shielding materials with excellent comprehensive performance can meet the requirements of military and civil applications.Electromagnetic shielding materials are developing towards light weight,easy processing and customizable.More and more researchers introduce the foaming technology into the field of electromagnetic shielding materials.After electromagnetic wave is injected into the foaming conductive glue,it will be reflected several times due to the existence of bubble holes,and the energy of electromagnetic wave will be converted into heat energy and dissipated.Due to the volume resistance effect of the bubble hole,the conductive packing can be dispersed and constructed a more uniform conductive network,which increases the electromagnetic shielding effect.In this paper,the non-isothermal curing properties of organosilicon conductive silicone rubber with different proportions were investigated by using dynamic thermal mechanical performance test(DMA)method.The initial temperature T_i,peak temperature T_pand end temperature T_eof curing peak at different heating rates were obtained through programmed temperature control and heating rateβ.The Kissinger method was used to calculate the slope K by linear fitting,and the curing activation energy Ea=K was obtained.The Ozawa method was used to plot 1/T_pwith-Lnβ,and the slope of the line was obtained by fitting.Then the curing activation energy Ea was calculated.Crane equation was used to plot 1/T_pwith Lnβ.Through linear fitting,the slope of the line-Ea/n R was obtained,and the reaction order n was obtained.The curing temperature and curing time can be deduced and the curing process can be determined,which provides basic data for the subsequent preparation of high-performance conductive silicone rubber and foamed silicone rubber.In this paper,water was used as the hydroxyl donor,and the conductive silicone rubber was foamed by dehydrogenation foaming method.Polysorbitol ester-20 was used as the surfactant to make silicone oil and deionized water fully mixed to increase the reaction degree of the hydroxyl group in water and the silica-hydrogen bond in hydrogen-containing silicone oil.By changing the temperature and the amount of inhibitors,the matching degree of foaming reaction and crosslinking reaction was achieved.Finally,foamed conductive silicone rubber with uniform bubble structure and excellent mechanical properties was prepared.It is a green and environment-friendly preparation process of foamed silicone rubber.In this paper,foam microspheres are used to foam conductive silicone rubber.Foam microsphere method is a technology that uses expandable microspheres to foam silicone rubber.Microspheres are generally composed of thermoplastic resin shell and inert gas/low boiling liquid core material.In this study,foam microsphere method was used for foaming modification,and through the adjustment of additives,foam silicone rubber with uniform bubble structure and good mechanical properties was prepared.Different from chemical foaming method of water foaming system,the foaming process was controllable,the process was simple,and the crosslinking and foaming process were easy to match.Through this study,the foam conductive silicone rubber material with excellent performance is prepared.While the composite material is light,it has excellent electromagnetic shielding effect.It can also be processed into electromagnetic shielding products of various shapes and thicknesses,so as to improve the signal security of 5G communication equipment and the level of 5G protection,and promote the development of Chinese information technology.