Preparation of flexible, highly conductive polymer composite films based on double percolation structures and synergistic dispersion effect

Abstract We studied for the first time the synergistic dispersion effect of the carbon nanotube (CNT)/graphene (Gr) and polypropylene (PP)/polycarbonate (PC) (1:1) double percolation structures on conductive polymer composites (CPCs). PP/PC/CNT/Gr films with different CNT/Gr ratios are prepared by melt blending and hot pressing. Results showed that a CNT/Gr ratio of 1:1 facilitated the creation of co‐continuous double percolation structures of matrices, and the electronic conductivity reached 33.11 S/m, which was five times greater than that of the matrices containing only CNT. Results showed that the synergistic dispersion effect and the co‐continuous double percolation structures provided the matrices with conductivity through an additive effect. Meanwhile, PP/PC/CNT/Gr composite films possessed good thermal stability and hydrophobicity. They also did not exhibit thermal degradation at 300°C and had a water contact angle of 94.5°. However, PP and PC were incompatible, causing considerable brittleness of composite films macroscopically, and the films can hardly curve. To respond to this downside and improve the flexibility, a small amount of thermoplastic polyurethane (TPU) was added to the system. The presence of TPU helped combining the two materials in different phases, thereby strengthening the continuity. However, the presence of TPU adversely affected the double percolation structures and dispersion state of fillers, and subsequently decreased the conductivity.