Manufacturing techniques and property evaluations of conductive composite yarns coated with polypropylene and multi-walled carbon nanotubes

This study uses a melt extrusion method, a method for producing wires, to coat polyester (PET) yarns with polypropylene (PP) and multi-walled carbon nanotubes (MWCNTs). The resulting PP/MWCNTs-coated PET conductive yarns are tested for their tensile properties, processability, morphology, melting and crystallization behaviors, electrical conductivity, and applications. The test results indicate that tensile strength of the conductive yarns increases with an increase in the coiling speed that contributes to a more single-direction-orientated MWCNTs arrangement as well as a greater adhesion between PP/MWCNTs and PET yarns. 8 wt% MWCNTs results in an 18 °C higher crystallization temperature (Tc) of PP and an electrical conductivity of 0.8862 S/cm. The test results of this study have proven that this form of processing technology can prepare PP/MWCNTs-coated PET conductive yarns that have satisfactory tensile properties and electrical conductivity, and can be used in functional woven fabrics and knitted fabrics.