Preparing Assembly Of Graphene Modified Conductive Composite Fibers With Functional Studies

In recent years,with the gradual deepening of scientific research,graphene and its derivatives in the field of textile applications are increasingly widespread,consumer demand continues to promote the new functional graphite textiles,cross-cutting development.The graphene composite conductive fiber have been the focus of functional fibers,generally refers to the fiber whose resistance rate is less than 108Ω·cm.It possesses electric conduction,electric heating and electromagnetic radiation shield,and usually used in concentration is applied in special occasions antistatic clothing or electromagnetic radiation shield clothing,and other fields.This topic prepared graphene composite conductive fiber by wet-spinning,pre oxidation,carbonization,continuous dip coating,dipping.The research work includes the following parts:Firstly,the polyacrylonitrile（PAN）solution,whose concentration was 15%,was prepared with PAN as raw materials and N,N-dimethyl formamide（DMF）as solvent.Then the solution was spun by the wet spinning machine.The best technological conditions of the wet spinning was the concentration of 4%,the concentration of the coagulation bath is 50%,the coagulation bath temperature of 20³0℃,the draft ratio of 4.22 times and hot drawing box of 130^°C by the single experiment of coagulation bath temperature,the draft ratio and hot drawing temperature.Secondly,polyacrylonitrile（PAN）microfibers incorporated with different contents of graphene oxide（GO）were spun via wet-spinning route in this work.Based on non-solvent-induced phase separation（NIPS）theory,N,N-dimethyl formamide（DMF）/water mixture system was employed as coagulation bath,non-solvent（water）diffused into PAN molecules and led to a quick PAN solidification.Polarized optical microscopy images of GO dispersions and GO/PAN formulations demonstrated nematic liquid crystal（LC）state of GO and the dispersion of spinning solution.The morphology and structure of composite fibers were characterized via SEM,TEM,FTIR and XRD.GO/PAN composite fibers performed outstanding mechanical properties.Compared to pure PAN,40%enhancement in tensile strength and a 34%enhancement in Young’s modulus were obtained of the composite fiber with 1wt.%GO.The results of dynamic thermomechanical analysis（DMA）indicated that the composite fiber with 1 wt.%GO performed the best thermal mechanical property with 5.5 GPa and 0.139 in storage modulus and loss tangent respectively.In addition,thermogravimetric analysis showed that thermal stability of the composite fibers enhanced with the increasing GO contents.GO/PAN composite fibers can be as the candidate of carbon fiber precursor,high performance fibers and textiles applications.Thirdly,nylon filaments incorporated with different contents of graphene（GR）were prepared via continues solution dip coating in this work.Waterborne polyurethane（WPU）/graphene mixture system was employed as functional chemicals,forming an ester bond between WPU and GR dispersed the GR evenly into the WPU,GR is firmly coated on the filaments surface due to strong adhesive capacity of WPU.The filaments obtained noticeable promotion in electrical conductivity.When the GR content reached 60%,the electrical conductivity of graphene modified nylon filaments before and after washing increased to 6.43 and 5.79 S/m respectively.The morphology and structure of graphene modified nylon filaments were characterized via SEM,FTIR and XRD.Compared to untreated nylon plain weave,60%GR modified nylon plain weave performed the best properties with doubling the thermal conductivity,hydrophobic（104.381°increasment in contact angle）and ultraviolet-shielding properties（less than 5%in UV transmittance and 416.19 in UPF）.The results and most of all,graphene modified nylon filaments were developed for possible application in wearable electronics as stretchable conductors or in strain sensors.In contrast,when the linear-type and knitted-loop-type strain sensor reached the maximum strain（13.64%and 45.69%）respectively,the gauge factor is G_linear=0.94 and G_knitted-loop=0.27.The sluggishness isγ_{H linear}=29.96%andγ_{H knitted loop}=21.83%.The electromechanical characteristic of the produced graphene modified nylon filaments was assessed experimentally by measuring resistance change of the produced specimen during tensile strength tests.It resulted that the breaking load and the resistance showed a synchronized change after elongation.By measuring relative resistance change（ΔR/R₀）of the produced multiform strain sensors based on graphene modified nylon filaments during various tensile deformation processing.It rasults that the produced specimen can monitor joint motion even belly breathing.Fourthly,configuration concentration of 1,2,3,4,5 mg/ml GO solution,dip with acrylic fiber.Then the preparation of the samples separately thermal reduction,oxidation and carbonization.The morphology and structure of all samples were characterized via SEM,FTIR and XRD.;And reduction of heat and the conductivity of samples after test,carbide after thermal reduction and carbonization the highest conductivity of samples after 0.137 S/m and 19.27 S/m,showing very excellent conductivity.