Preparation Of Polyurethane-based Graphene-coated Geotextile Fabric For Construction And Research On Its Electromagnetic Propertie

Low frequency electromagnetic waves have been certified as carcinogens by the International Agency for Research on Cancer,so it needs to be shielded to protect human health.In recent years,with the development of electronic information technology,low-frequency electromagnetic waves have penetrated into our lives.For example,the 5G signal frequency of the three major domestic operators is 2.515～ 3.6GHz,and the frequency of microwave ovens is between 915～2450 MHz.At present,civil buildings generally only meet the basic needs of life,it is difficult to reduce the harm of electromagnetic wave to human body.In order to solve this problem,this topic takes 0～3 GHz frequency as the research range,and prepares the absorbing coating geotextile fabric for building.Firstly,polyurethane based single-layer coated geotextile fabric was prepared by coating process using common wave absorbing materials(silicon carbide,carbon fiber powder,graphite,copper powder,barium ferrite)as functional particles,polyethylene geotextile for construction as base cloth,PU2540 polyurethane as base cloth.The effects of different content on the electromagnetic properties(reflection loss,dielectric properties,surface resistance)and other properties(sound absorption,tensile properties,wear resistance)of coated fabrics were studied.Secondly,r GO was prepared by chemical reduction method and its chemical structure was characterized.Then,using graphene as the functional particle,polyethylene geotextile as the base cloth and PU2540 polyurethane as the matrix,polyurethane foundation graphite monolayer coated geotextile fabric was prepared by coating process.The effects of reducing agent type,reducing agent concentration,reduction time and GO concentration on the electromagnetic properties and other properties of coated fabrics were studied by using control variable method.Finally,the common absorbent materials on the market and the prepared r GO were used as functional particles to prepare the coated fabrics,and the functional comparison was conducted,including electromagnetic properties and other properties.The main conclusions are as follows: Compared with common functional particles,when graphene is a functional particle,the reflection loss and surface resistance of coated fabric are the lowest,which are-21.525 d B and 12.48 KΩ,respectively,and more than 99% of the electromagnetic wave is absorbed.Sound absorption and tensile properties are the best.Therefore,the geotextiles with polyurethane base ink monolayer coating have good electromagnetic protection,sound absorption and tensile properties.Results show that the synthesized graphene is stacked sheet with a thickness of less than 5 μm.There are two characteristic peaks in the spectra,corresponding to(002)and(101)crystal planes respectively.The characteristic peak of 20°～31° is a broadened dispersion peak.After reduction,the C/O ratio of GO increased from 2.6 to 5.15,indicating that the oxygen-containing group was removed.The oxidation peak weakened or even disappeared after reduction.After 400 ℃,the mass residual was 77.9%,indicating that the thermal properties of prepared graphene were stable.