Preparation And Research On Polyurethane Modified By Inorganic Nanocomposite

With the rapid development of modern science and technology,many electronic devices in various fields have brought great help to people's life and the radar of military.However,these electronic devices will produce harmful electromagnetic interference and radiation while working.Electromagnetic radiation has become a new environmental pollutant.However,a single absorbing material can't meet the needs of various fields,so it is necessary to prepare light-weight and excellent absorbing composites.Polyurethane?PU?is widely used in aerospace,biomedicine and civil industry as coatings and adhesives.If polyurethane was modified by inorganic nanocomposite,it will have a broader application prospect.Carbon nanotubes?CNTs?have excellent physical properties such as high flexibility,high conductivity,high thermal conductivity,high tensile strength and high aspect ratio.Therefore,they are potential materials for designing electromagnetic wave absorbers.Manganese dioxide?MnO₂?is low cost,friendly environment and high natural abundance,and has been used as supercapacitors,sensors,field emitters,electromagnetic wave absorption and so on.First,multi-walled carbon nanotubes/manganese dioxide?MMCs?nanocomposites were prepared by coprecipitation method,then they were modified by siloxane to obtain the modified MMCs nanocomposites?mMMCs?.The structure and properties of the mMMCs were analyzed by infrared spectroscopy,X-ray diffraction and scanning electron microscopy.A series of mMMCs/PU composites with different mass ratios of manganese dioxide to multi-walled carbon nanotubes were prepared in-situ polymerization by introducing mMMCs nanocomposites into PU.And the properties of mMMCs/WPU composites were characterized by static mechanical analysis,surface property test,thermal stability analysis and microwave absorption performance analysis.The experimental results shown that the mechanical and thermal stability of mMMCs/WPU composites were improved by adding mMMCs nanocomposites.At the same time,when the ratio of MWCNTs were 20 wt%,the thickness is2.5 mm,the mMMCs/WPU composites have excellent absorbing properties,and the minimum RL value is-28.7 dB at 6.4 GHz.Compared with MoS₂ and graphene,WS₂ has larger interlayer spacing,stronger radiation resistance and thermal stability than that of graphite and MoS₂,and its single electron mobility is also high.Therefore,WS₂ nanosheets have good application prospect in the field of electromagnetic wave absorption.The tungsten disulfide/multi-walled Carbon Nanotubes Nanocomposites?WMCs?were synthesized by a simple hydrothermal method.The surface of WMCs nanocomposites was modified by siloxane to obtain SWMCs nanocomposites.Finally,the SWMCs nanocomposites were introduced into polyurethane by in-situ polymerization,and a series of SWMCs/PU composites with different mass ratios of tungsten disulfide to multi-walled carbon nanotubes were prepared.Their structure was analyzed by infrared spectroscopy,X-ray diffraction and scanning electron microscopy.And their properties were characterized by static mechanical analysis,surface performance test,thermal stability analysis and microwave absorption performance analysis.The results shown that the mechanical and thermal stability of SWMCs/PU composites were improved by adding SWMCs nanocomposites.At the same time,when the mass ratio of WS₂ to MWCNTs were 5:3 and 5:4,the thickness was 3 mm,the SWMCs/PU composites have good absorbing properties,and the minimum reflective loss?RL?were-31.8 dB and-35.2 dB,respectively.