Preparation Of PANI/PET And PPY/PA66 Composite Conductive Fabrics And Study Of The Properties

Polyaniline shows an attractive application prospect in many respects, because of its cheap raw materials, high conductivity, easy to prepare and doping, stable characteristics, etc. However, Polyaniline and polypyrrole are difficult to process for its insoluble and non-melting. The synthetic fibers with Polyaniline and polypyrrole composite layer in the surface are ideal materials for preparing flexible electromagnetic shielding materials and smart textiles. Because they not only have resilience and flexibility of the fabric, but also have higher conductivity of Polyaniline and polypyrrole. How to further enhance the conductivity and stability of the conductive fibers and fabrics, and keep the performance and practical value of the fibers or fabrics, and find a simple preparation method which costs are lower are the common goal of all researchers. In this study, Polyaniline was synthesized at the surface of polyester fabric and pyrrole was synthesized at the surface of nylon66 by in-situ polymerization method. The effects of main factors to the conductivity of the fabric were researched to make the conductive fabric have flexibility and better conductivity.We studied the effects of main factors including the concentration of aniline monomer, initial molar ratio of oxidant ammonium persulfate and aniline, type and concentration of the doping acid, and reaction time to the conductivity of the PANI / PET composite fabric. The results showed that when the aniline monomer concentration was 0.25mol / L, the molar ratio of oxidant and aniline was 1:1, the concentration of doping acid was 0.5mol / L, the reaction time was 60min, the conductive fabric had the best conductivity. We also studied the pyrrole monomer concentration, the initial molar ratio of oxidant FeCl₃ and pyrrole, concentration of the doping acid, reaction time and reaction temperature on the effects of conductivity of PPy / nylon 66 composite fabric. The results showed that when the concentration of pyrrole monomer was 0.05mol/L, initial molar ratio of FeCl₃ and pyrrole was 1:2, the concentration of doping acid was 0.05mol / L, the reaction time was 3h, the conductive fabric had the best conductivity.The structures and properties of the PANI/PET and PPY/PA66 were studied. FTIR showed that the surface of fiber was covered by Polyaniline and the content of oxidation structure and reduction structure in Polyaniline chain structure was basically the same. The surface of nylon66 fabric was indeed covered by conductive layer- polypyrrole, but the content was small. XRD showed that the conductive polymers not only deposited on the surface of the fiber, but also infiltrated the fiber and damaged the internal structure of the fiber, so that the crystallinity of the fiber reduced. SEM test showed that there were uniform and continuous conductive polymer films on the surface of fabric to form conductive pathways in the composite material. TG and DSC thermal analysis showed that the join of Polyaniline prevented thermal degradation of polyester fabric and improved its thermal stability. While the melting point of nylon 66 fabric changed little after composited with polypyrrole. That may be due to the low amount of polypyrrole in the fabric. So it had little effect on the melting point. Mechanical properties test showed that the composite fabrics kept their original mechanical properties basically. The moisture absorption of PANI/PET was improved. While the moisture absorption of PPY/PA66 was reduced.The stability of the conductivity of the composite fabrics was also investigated in this paper. For the PANI / PET composite conductive fabric, the results showed that, 1. the conductivity decreased after treated by chloroform, toluene, acetone, ethanol; 2.after heat treatment the resistance of conductive composite fabric increased, but in a certain temperature range,it increased little; 3.the resistance increased little after salt corrosion. For the PPY / PA66 composite conductive fabric, 1. The conductive fabric which didn't add dopant and doped with p-toluenesulfonic had good environmental stability. While the conductive fabric doped with hydrochloric acid had poor environmental stability; 2. The conductive fabric doped with p-toluenesulfonic acid had relatively stable conductivity after treated by acetone, ethanol, toluene, chloroform, hydrochloric acid; 3. The conductive fabric doped with p-toluenesulfonic acid had excellent thermal stability.