Polycarbonate (PC) is a high molecular polymer with carbonate groups in its molecular chain. Due to its unique structure, PC has become one of the fastest-growing general engineering plastics among the five major engineering plastics. During the production of engineering plastics, conductive carbon black needs to be added to PC. This article introduces the role of adding conductive carbon black to PC plastics and the issue of carbon black content in polycarbonate.
The role of adding conductive carbon black to PC plastics
Conductive and antistatic PC plastics are blends of PC raw materials with carbon fibers, carbon black, metal fibers, metal powders, permanent antistatic masterbatches, etc. They can achieve functions such as antistatic, electrostatic dissipation, dust prevention, conductivity, and electromagnetic interference (EMI) shielding. Conductive and antistatic PC plastics have high mechanical strength, impact resistance, good dimensional stability, excellent creep resistance, heat resistance, cold resistance, and can be used for a long time at temperatures ranging from -40℃ to 120℃.
PC carbon black conductivity
The material for PC carbon black conductivity is PC carbon black grade, with a surface resistivity range of 103 -105Ω. The common production processes are injection molding and extrusion, and the main applications are in edge materials, pipe materials, communication equipment, electrical enclosures, electronic components, and other products.
PC carbon black antistatic
The material for PC carbon black antistatic is PC carbon black grade, with a surface resistivity between 106 -109Ω. The common production processes are injection molding and extrusion, and the main applications are in edge materials, pipe materials, automotive parts, electrical enclosures, electronic components, and other products.
Carbon black content in polycarbonate
Carbon black is one of the important factors affecting the PTC effect. When the percolation threshold is reached, the PTC effect will increase as the carbon black content in the system decreases. Compared with the carbon black/PP/PC composite material filled with acetylene black and furnace black, the former has lower volume resistivity, while both have similar percolation thresholds of 6.6%. For the carbon black/PP/PC ternary composite material filled with acetylene black as the filler, the AC transition temperature is around 140℃, while for furnace black as the filler, the PTC effect transition point appears around 150℃ (PC's Tg). DSC analysis results show that the crystallinity of PP in the composite material increases with the increase of carbon black content and reaches 32.75% when the carbon black content is 15%. The crystalline part of the entire PP/PC/carbon black system is relatively low, so the PTC effect strength of the system is also relatively low.