Research On Properties Of Carbon Black/Polypropylene Composite By Dynamic Injection Molding

Polymer-matrix composites with conductive fillers are becoming increasingly availablefor electromagnetic shielding, which will gradually replace traditional metal materials.However, they still have poor processability and mechanical properties. This paper researchedon the influences of vibration force field on the electrical and mechanical properties ofcomposite products with variable contents of CB filler by adopting CB/PP composite systemand dynamic injection molding for finding the optimum ranges in which composite systemresponded to the vibration effects effectively. Meanwhile, this paper focused on the influencesof molding processes on the mechanical properties of the composite products with introducingvibration force field.Research on the properties of CB/PP composite products by dynamic injection moldingshowed that the introduction of vibration force field could effectively improve the electricalconductivity distribution differences in different parts of the composite and the fallings ofmechanical properties of composite with CB filler contents increasing. Especially when thecontent was30wt%, the effects were the most obvious. The percolation phenomenon ofconductivity of composite occurred at15wt%and the calculated SE at2GHz had positivecorrelation with the variation trends of conductivity. The calculated SE of composite wasmore than30dB at30wt%, which could possess good shielding effects. By respectivelychanging the amplitudes and frequencies, at5Hz, the optimum area of electrical andmechanical properties was60~90; at25Hz, was10~30; at90, was5~15Hz; at30,was20~25Hz, which optimized vibration parameters for producing electromagnetic shieldingcomposite. Without vibration, molding process parameters had significant effects on thecomposite system. After introducing the vibration force, the adaptability of the compositesystem with the variation of process parameters had been improved effectively, which showedthat vibration force field could improve the processability of composite.