Poly(urethane urea)/polythiophene/carbon black composite

Abstract

Novel segmented poly(urethane urea) (PUU) was prepared from polycaprolactone triol (soft segment), 4,4′-methylenebis(phenyl isocyanate) (hard segment), and hexamethylenediamine (chain extender). Graphitized carbon black (GCB) was used as filler. Conducting polythiophene (PTh) was infiltrated by chemical oxidative polymerization. The structure, morphology, mechanical properties, electrical conductivity, and voltage-triggered shape memory effect were demonstrated. The unique network morphology was observed by scanning electron microscope due to the generation of interpenetrating polymer networks (IPNs). The formation of PUU-PTh IPNs was due to the interpenetrating PTh and branched polycaprolactone triol structure. The PTh-modified PUU films reinforced with GCB showed 59% increase in tensile strength and 50% enhancement in Young’s modulus relative to the pristine matrix. The presence of PTh and increase in GCB content increased the conductivity of the composites. The conductivity of 10 wt% GCB-loaded PUU/PTh/GCB composite was raised to 0.089 Scm−1, which is higher than the neat PUU (0.91 × 10−2 Scm−1). The surface temperature of PUU/PTh/GCB 10 was also found to increase with time when a higher voltage was applied (40 V). Such a conductivity of composites was enough to show electroactive shape recovery up to 94% (40 V).