Shape memory effect and mechanical properties of carbon nanotube/shape memory polymer nanocomposites

Carbon nanotubes (CNT) have remarkable mechanical properties with very high elastic modulus and electrical conductivity. Shape memory polymer (SMP) as one of smart materials is characterized with its remarkable recoverability and shape memory effect, but its mechanical properties such as strength and elastic modulus is not high enough. In this study, CNT/SMP nanocomposites were developed with the typical CNTs of the vapor growth carbon fibers (VGCFs). A fine and homogeneous dispersion of VGCF throughout the SMP matrix is obtained. The specimens with different VGCF weight fraction, such as SMP bulk, 1.7 wt.%, 3.3 wt.% and 5.0 wt.%, were prepared, and their dynamic mechanical properties and shape recovery behavior were investigated. It was found that storage elastic modulus is improved obviously with increment of VGCF weight fraction, and the CNT/SMP nanocomposites showed a good shape memory effect. It is indicated that the recovery stress of CNT/SMP nanocomposites with only 3.3% weight fraction of carbon nanotubes will reach almost twice of that in SMP bulk.