Fabrication And Applications Of Conductive Poly(Ethylene Terephthalate) Nonwoven Fabrics

With the progressing of information technology and growing awareness of healthcare,functional fibers and fabrics have attracted more and more attention.Since the 1990s,smart fibers and fabrics which combine the flexibility and knittability of traditional fibers and various functional properties have attracted more attention.For example,conductive fibers and fabrics have been applied in many fields such as electric heating,sensor,energy storage,adsorption and catalysis.Recently,a new kind of conductive fibers and fabrics has been fabricated by using graphene-based materials through blend spinning or post-treatment processes,especially more attentions have been paid to post-treatment of traditional fabrics due to its low price,simple process and no special demand for equipment.Until now,most of the graphene composite fibers and fabrics have been fabricated by immobilizing insulating graphene oxide(GO)on the surfaces of fibers or fabrics and then further converted into conductive graphene.In this work,a low-cost approach would be presented for dyeing PET nonwoven fabrics by anchoring the reduced graphene oxide(rGO)sheets on the surface of the fabrics in aqueous system.The structure and properties of as-prepared composite fabric would be characterized and the feasibility of using the composite fabrics as heating and gas-sensing elements would be evaluated.The main results and conclusions are listed as follows:(1)Optimization of the preparation process for conductive PET nonwoven fabrics:The stability of graphite,graphite oxide and reduced graphene oxide in aqueous dispersions were evaluated,and the morphology and structure of rGO sheets as conductive particles were characterized.Great improvement in the structure stability of composite fabrics could be achieved by introducing polyurethane as thin adhesive layer.The preparation conditions were optimized to obtain uniform coverage of rGO on the surface of the composite fabrics and high conductivity.Furthermore,a series of composite fabrics were fabricated in aqueous dispersion with different rGO contents.(2)Structure and properties of conductive PET nonwoven fabrics:The change on the morphologies of composite PET fabrics was observed with the increasing rGO content in aqueous dispersion.The chemical structure of composite fabrics was characterized by FT-IR and Raman spectroscopy,and the results indicated that the hydrogen bonding played an important role in bonding PET and rGO together through thin PU layer.Moreover,the percolation theory was used to describe the change in conductivity of composite fabrics with the increasing of the rGO fraction.In addition,thermal stability of the composite fabrics was evaluated by thennal gravimetric analysis and structure stability by ultrasonic treatment and mechanical stirring process,respectively.Good conductivity and high structure stability of the composite fabrics could be achieved.(3)Application of conductive PET nonwoven fabrics:Firstly,the feasibility of the composite fabrics as heating element was demonstrated by recording the change in the ambient temperature as a function of the time by applying different constant voltages.Then the adsorption behaviors of composite fabrics for different organic vapors,such as ammonia fumes,methyl alcohol,acetone,formaldehyde and methylene chloride,were investigated,and especially the sensing behavior for ammonia fumes were evaluated.In this work,a simple one-step dyeing-like approach was presented for fabricating conductive PET nonwoven fabrics by using rGO sheets instead of GO as dyestuffs.Though no significant improvement in the conductivity of composite fabrics compared to those prepared by two-step process with GO as dyestuffs,great enhancement in the structure stability was achieved.More importantly,this kind of composite fabrics would provide a suitable platform for further fabricating functional conductive fabrics.