Low-voltage triggered electroactive and heat-responsive thermoplastic elastomer/carbon nanotube polymer blend composites

Abstract

This study presents the synthesis and characterization of novel polymer composites that are triggered by heat and electricity. The composites were made of a blend of a styrenic block copolymer and a thermoplastic polyolefin elastomer, with multi-walled carbon nanotubes (MWCNTs) added as fillers. The composites were prepared through melt blending and the amount of MWCNTs was varied from 1 to 10 phr. The results of morphological characterization showed that the distribution of fillers within the matrix improved as the amount of MWCNTs increased. The crystallization temperature was also found to decrease due to the nucleation effect of the fillers. The reinforcing effect of MWCNTs resulted in increased values of elastic modulus, creep resistance, and storage modulus, while decreasing the values of elongation at break, creep recovery, and damping parameter (tanδ). The electrical resistance of the composites decreased with increasing amounts of MWCNTs, with the lowest resistance recorded in the composite which contains 10 phr MWCNT (10CNT) composite at 12 ohm.cm. The 10CNT composite was also able to be heated up to 75 °C by Joule heating at a voltage of 5.5 V. The shape fixing performance of the blend improved in the presence of fillers, however, despite an increase in the recovery stress value, the heat-responsive shape recovery feature worsened. The composite having 5 phr MWCNT (5CNT) showed electro-active shape recovery under 25 V in 210 s, while the 10CNT composite completed this process in 300 s under 5.5 V. The results of this study demonstrate the potential of using MWCNTs as fillers in polymer composites for various applications that require both electrical conductivity and heat responsiveness.