Research And Preparation Of Phenolic Resin-based Aluminum-glass Fiber Electromagnetic Shielding Materials

As society into the 21st century, the development of science as well as the extensive use of electrical equipment causes a series of social and security issues such as the rise of electromagnetic radiation, electromagnetic leaks and electromagnetic pollution, this has seriously affected people's life and work. The traditional shielding paint and metal plates can no longer meet the requirements of shielding, especially the frequency and intensity of electromagnetic wave are growing, so study and prepare such EMS material which can shield electromagnetic wave that have a high and wide frequency is a hot spot in nowadays.In this paper, we have prepared a composite material which has been heated and pressurized, and four-point probe, electromagnetic shielding effectiveness instrument and FESEM were employed to characterize the structure and properties of the material, respectively. We discussed the relationship between the filled volume, the structure of the material and the shielding effectiveness, and the difference between classic model curve and measured curve is also clarified. The material which we prepare has a high shielding effectiveness and can be used in a wide range of frequency.The research result show us that: the percolation threshold is lower than 0.15, and the shielding effectiveness(SE) will maintain a constant when filled volume rise to 40%～60%, but drops when keeping rising. Besides, carbon blacks can upgrade the conductivity but SE, and adding common glass fiber will decrease the SE. The research of fiber length show us the SE will not increase with the extending fiber length, the highest SE only can be acquired in a appropriate fiber length.Different SE curves between the prepared material and the single layer structure material tell us, the SE is higher when the material has a multilayer structure, and this gap will expand while frequency is higher. Besides, the classic model can not precisely express the conductive network model, this is because inductive reactance loss, at last the paper has estimated inductive reactance loss is about 7dB when the frequency is 1200MHz.