Fabrication And Investigation Of PSA/PEDOT Conductive Composite Yarns

The polysulfonamide(PSA) fiber is one of the organic high temperature fibers developed by Chinese with full Intellectual property rights; it has some excellent properties such as heat resistance, thermal stability and flame resistance etc. However, the electrical resistance of the raw PSA fiber is relatively high; these properties cause some difficulties during its manufacturing process and limit its application in the development of functional textile products. Poly(3,4-ethylenedioxythiophene)(PEDOT) has been considered as a new type of conductive polymer materials, which attracts considerable attentions of scientists due to its molecular structure simple, less energy gap and high electrical conductivity etc. In order to develop some high-tech conductive yarn, polysulfonamide yarn and PEDOT have been selected as the substrate and the coating material.PSA/PEDOT conductive composite yarns were produced by vapor phase polymerization(VPP) to form PEDOT layers on the surface of PSA yarns.Scanning electron microscopy(SEM) and FTIR analysis had been used for the morphology and component analysis, which could be used to reveal the polymerization of PEDOT on the surface of PSA yarns. Thermogravimetric analysis(TG) was utilized to investigate the thermal properties. The effect of PEDOT coating on the mechanical properties of the PSA yarn was evaluated by tensile strength testing of the coated yarn. The effects of polymerization conditions, including reaction time, oxidant concentration and soaking time of PSA yarns in oxidant solution on the electrical conductivity of yarns, were investigated systematically in this study. In addition, the conductive mechanism and electric heating properties of PSA/PEDOT conductive composite yarn were studied. The electricl heating performance of PSA/PEDOT conductive composite yarn with traffic circle,skein, series connection and parallel connection structures was researched.In order to investigate the effect of conductivity of composite yarn with different performance yarn and different structure, PA6/PEDOT conductive composite yarn,PET/PEDOT conductive composite yarn and PSA/PEDOT conductive composite fabricwere produced.The experimental results show that:1) The optimized process of preparation of PSA/PEDOT conductive composite yarns could be carried out at 80℃ for 10 min with ferric(Ⅲ) chloride(Fe Cl3) oxidant 80g/L,reaction time 10 min and soaking time 60 min, and the mass-specific resistance reached0.94?2??? cmg.2) The PEDOT-coated films on PSA yarns, which are the smooth and compact, have been proved to be fabricated successfully by the method of VPP, through the observation of SEM images and FTIR curves. PEDOT of PSA yarns surface could form complete conductive path, which endows polysulfonamide yarns with excellent conductive properties. The results of TG analysis show that the thermal stability properties of PSA/PEDOT conductive composite yarns are better than the pure PEDOT membrane.3) The propeties and structure of substrate yarn have effects on the electrical properties of conductive composite yarn. The conductivity order from high to low of conductive composite yarns in this experiment is : Polysulfonamide > Polyester >Polyamide 6. Furthermore, the environmental stability of PSA/PEDOT conductive composite yarns is good. With the variance of the conditioning time, temperature and washing times, the mass-specific resistance of conductive composite yarns increases, while the conductivity of conductive composite yarns decreases, and eventually both of them tend to be stabilized.4) The test of mechanical properties shows that the strength and elongation are affected by the oxidant treatment. With increasing oxidant concentration, mechanical properties of PSA/PEDOT conductive composite yarn are reduced. But when oxidant concentration reaches a certain value, the strength of the PSA/PEDOT conductive composite yarn stabilized.5) From the analysis with cyclic voltammetry, the conductivity of conductive composite yarns could be determined by the Ohm’s law. Under DC conditions, conductive composite yarns can be used as the purely resistance material. The temperature of PSA/PEDOT conductive composite yarns during the electrically heated process tends to increase as the apllied voltage increases. However, with the extension of time the heating temperature of PSA/PEDOT conductive composite yarns increase firstly and then tend to stabilization.6) The fabric substrate, traffic circle, skein, series connection and parallel connection structures of PSA/PEDOT conductive composite yarns all have good electric heating performance. Comparing the yarn which was extracted from the deposition fabric with the yarn which was deposited directly, found that both of them were coated with PEDOT completely. The result of the deposition of two yarns has no difference.Conductive yarns are a key component in future smart textiles being widely used as power and signal transmitter and in sensors, actuators, and controlling units. The PSA/PEDOT conductive composite yarns were fabricated by the method of vapor phase polymerization in this study. The PEDOT-coated PSA yarn is conductive and could generate heat that would have application prospects in various fields such as wearable equipment for military, medical care, etc.