The Electromechanical Properties of Crosslinked Natural Rubber

The effect of electric field strength on the electromechanical properties of crosslinked natural rubber for use in actuator applications was investigated. The physical and electrical properties of crosslinked natural rubber with various crosslinking ratios were measured under an applied external electric field. A parallel-plate melt rheometer was used to measure the storage modulus and the loss modulus of the crosslinked natural rubber. All experiments were conducted in the linear viscoelastic regime, in the frequency range of 0.1-100 rad/s and at 1% strain. In the absence of an applied electric field, the storage modulus increased with deceasing crosslinking ratio because of the greater amount of strands in the rubber gel. When the external electric field was applied, the storage modulus increased because of the electrostatic force between the crosslinking points. At each crosslinking ratio, the storage modulus was higher than the loss modulus because of the solidity of the materials. Thus, the crosslinked natural rubber reported here may represent an inexpensive and highly electroresponsive material with good mechanical properties for artificial muscle applications.