Relationship Between Strain and Electrical Resistivity of Vulcanized Rubber Filled with Carbon Nanofiber

Rubber material generally behaves as an electrical insulator, but vapor-grown carbon fiber (VGCF) is known for its electrical conductivity. Thus, we compounded styrene-butadiene rubber and carbon nanofiber (VGCF), and studied the relationship between strain and the DC electrical resistivity of vulcanized rubber filled with carbon nanofiber. No change of hardness was observed in hardness tests. VGCF has a reinforcement effect similar to carbon black (CB). The volume electrical resistance decreases with an increase in VGCF concentration, and the relationship is nonlinear. The volume electrical resistance of rubber with VGCF increased when the sample was extended. The change rate is related to the parts and contents of the fillers. The relationship between strain and electrical resistance of rubber with VGCF is suitable for application as a strain sensor.