Research On High Thermal Conductivity Electromagnetic Shielding Auxiliary Material For Flexible Materials Based On Graphene Composite Technology

Graphene is a spatially planar six-membered ring structure material composed of two-dimensional sp²bonded carbon atoms.Due to its unique intrinsic structure,graphene exhibits excellent performance in many fields and has become the focus of scientific research and various application fields.hot spot.Similar to the microstructure of columnar carbon nanotubes（CNT）,it also has excellent mechanical,electrical and thermal properties.Based on this,some researchers have used various forms of graphene materials as nano-reinforcers to make polymer-based composite materials obtain versatility.Such research has involved many fields and formed preliminary products.However,due to the hydrophobicity and chemical inertness of graphene materials,using them as nanoparticles will make their compatibility with the polymer matrix worse.In addition,the high cost of graphene materials and small output have become the main obstacles restricting its industrial application.On the contrary,graphene oxide,as a derivative product with the same structure as graphene,can eliminate some of the shortcomings of graphene nanofillers.At the same time,the base surface of the graphene oxide is functionalized with hydroxyl groups and other groups,and the carboxylic acid functional groups at the edges are functionalized.The functional groups on the surface of GO can not only interact strongly with hydrophilic polymers,but can also provide grafting points for chemical modification,and are used as fillers to prepare composite materials for a variety of polymer matrices.These excellent properties make GO a valuable Promising material.Water-based polyurethane（WPU）is a commonly used additive in the textile industry.Due to its wide application range,strong performance,and no pollution to the environment,it has been well developed in recent years and is often used in daily life,such as indoor wood coatings and automobiles.Finish.Studies have shown that adding various nano-fillers（such as CNT,nano-clay and nano-silica）to WPU can improve the corrosion resistance,hardness,flame retardancy and other properties of WPU to a certain extent.In this thesis,WPU is selected as the matrix material,because GO has excellent mechanical properties,good dispersibility in water,and interaction with various polar groups in WPU,making GO particularly attractive as a nanofiller.However,the dispersibility of GO in the WPU matrix is still a difficult problem.In this thesis,in order to overcome the difficulty of GO dispersion and prepare composite nanomaterials with high thermal conductivity and electromagnetic shielding performance,the contents are as follows:（1）The"accordion"graphene oxide（AGO）is prepared by the modified Hummers method and the optimized oxidation method（normally standing still）respectively.The normal standing process is achieved by carbocation-induced interlayer oxygen release..The graphite layer can transfer electrons to hydrogen peroxide（H₂O₂）to form carbon,which in turn oxidizes H₂O₂to release O₂and expand the space between graphite layers.AGO was characterized by FT-IR,XRD,TG-DTG,Raman,SEM,TEM,and compared with GO.The results showed that the interplanar spacing of AGO was 0.85 nm,which increased the interplanar spacing by 0.14 nm compared to GO.From the microscopic morphology,it can be seen that AGO has fewer flakes and better dispersibility,which can be better dispersed in the matrix of water-based polyurethane,and at the same time improve the performance of water-based polyurethane.（2）Using polyethylene glycol（2000）,isophorone diisocyanate（IPDI）,dimethylolpropionic acid（DM PA）,triethylamine（TEA）,and silane coupling agent（KH550）as raw materials to prepare water For polyurethane（WPU）,set the R value to 1.1-1.5,and perform FT-IR,emulsion stability,particle size analysis,and TG-DTG test characterization for water-based polyurethanes with different R values.The results show that when R=1.2,The prepared waterborne polyurethane has the best stability.（3）By using WPU with an R value of 1.2 as the matrix and compounding with the prepared AGO,an AGO/WPU composite nanomaterial with an AGO content of0.6-1.2 wt.%was prepared,and subjected to FT-IR,XRD,TG-DTG,and stretching.The strength,SEM,TEM,thermal conductivity,and electromagnetic shielding performance test analysis showed that with the increase of AGO in the matrix,the mechanical properties,thermal conductivity and electromagnetic shielding performance of the composite nanomaterials have been greatly improved.When the AGO content is 1.0 wt.%,the tensile strength is increased by 31%;the maximum heat flow reaches 2120.51 W/（m²）,which is an increase of 92.8%,and the thermal conductivity reaches the maximum value of 0.71,which is an increase of 109%compared with the blank sample.;At the same time,the maximum shielding effectiveness reaches 18.46 d B,which is an increase of 463%compared with pure WPU coated fabric.When the AGO content is 1.2 wt.%,the thermal conductivity and electromagnetic shielding performance are reduced.