Research Of Preparation Process Of Conductive Rubber Used In Electromagnetic Shielding

With the rapid development of electronic information industry, the proportion of electronic products and equipment in people's daily life increases significantly. Electromagnetic interference caused by electromagnetic leakage in electronic products and equipment has been noticed gradually. As a new type of electromagnetic shielding material, conductive rubber(CR) possesses excellent electromagnetic shielding effectiveness(SE). The good adaptability of conductive rubber to engineering strcutrues leads to the wide application and recognization. Investigating the preparation procedure of CR from a view of thermodynamics and modifying the preparation process, can be of practical significance to improve the properties of CR.Focusing on the preparation procedures of conductive fillers and CR, the preparation processes was carried out respectively via studying the influences of different thermodynamic procedures during the preparation processes on the structures and properties of the corresponding materials. The properties of CR were evaluated.In the preparation procedure of nickel-coated aluminum(NA) powder, the temperature variation of electroless plating was regulated by changing the start-up times of circulating water-cooling device. The results indicated that start-up time of circulating water-cooling device had effects on the peak temperatures of displacement reduction and reduction reaction, and the time for electroless plating would cost. Starting the circulating water-cooling device when displacement reduction started could homogenize the coating and improve the production of NA powder.Post curing process could obviously enforce the stability of electrical conductivity of CR, while increase Shore A hardness. When post-curing time was 10 min, the SE of CR could maintain over 80 d B in 40 days, and CR achieved good flexibility. The heat conduction model of post curing was built, and series-parallel models and Lumped Parameter Analysis Method were selected to calculate the theoretical post-curing time whose result 626 s and consistent with experiments. In the curing process, stability of electrical conductivity and crosslink density of CR could be improved under pressurefree curing condition, because more crosslink structure was built due to the most unstrained molecular and enforced crosslinking reaction in this situation.Finally, the performance of CR was evaluated, and the contact corrosion behavior of CR with metal was investigated. CR with stable SE possessed cost advantage. When served in high temperature and humidity environment, CRs filled by NA and nickel coated graphite(doped with nickel coated carbon fiber) reached higher reliability.