Jian-Hua Tang

Segregated Conductive Ultrahigh-Molecular-Weight Polyethylene Composites Containing High-Density Polyethylene as Carrier Polymer of Graphene Nanosheets

This article reports a novel conductive ultrahigh-molecular-weight polyethylene (UHMWPE) composite with a segregated and double percolated structure, in which graphene nanosheets (GNSs) form prefect conductive pathways in the high-density polyethylene (HDPE) and the GNS/HDPE component forms continuous conductive layers at the interface between the UHMWPE granules. The combination of segregated and double-percolated GNS conductive network achieved an ultralow percolation of 0.05 vol. %. Structural observations and the determination of the critical exponent t-value obtained from the classical threshold mechanism indicate the formation of a two-dimensional GNS network in GNS/HDPE/UHMWPE composites. Comparison of the electrical performance of GNS and CNT-filled segregated composites indicated that the geometry of the conductive nanoparticles can greatly affect the dimensionality of the segregated conductive network.

Nonlinear current-voltage characteristics of conductive polyethylene composites with carbon black filled pet microfibrils

Current-voltage electrical behavior of in situ microfibrillar carbon black (CB)/poly(ethylene terephthalate) (PET)/polyethylene (PE) (m-CB/PET/PE) composites with various CB concentrations at ambient temperatures was studied under a direct-current electric field. The current-voltage (I-V) curves exhibited nonlinearity beyond a critical value of voltage. The dynamic random resistor network (DRRN) model was adopted to semi-qualitatively explain the nonlinear conduction behavior of m-CB/PET/PE composites. Macroscopic nonlinearity originated from the interfacial interactions between CB/PET micro fibrils and additional conduction channels. Combined with the special conductive networks, an illustration was proposed to interpret the nonlinear I-V characteristics by a field emission or tunneling mechanism between CB particles in the CB/PET microfibers intersections.