| Industries such as iron steel and electricity generation consume huge amounts of energy and are in urgent need of upgrading and promoting efficient energy-saving technologies,and energy efficiency improvement projects are also a key project for energy saving and emission reduction.There are two traditional approaches to solve these problems in the industry:one is to upgrade equipment to improve energy utilization;the other is to use certain materials during production and transport to reduce energy dissipation.Infrared radiation materials are currently used in industrial production as coatings which are applied to the interior of equipment to improve energy efficiency,and this material application method can adapt to any form of equipment,but the use of strength is poor,easy to crack,peeling.In recent years,the preparation of inorganic nanofibers with infrared radiation properties has developed considerably.The material prepared by electrospinning has the advantages of controlled morphology and easy preparation,while the purity of the prepared materials is high and the performance of the materials can be best presented.Therefore,it is of vital significance to give the form of nanofibers to infrared radiation materials and develop flexible nanofiber films with mechanical properties and high infrared radiation properties.In this project,chromium nitrate anhydride,lanthanum nitrate hexahydrate,and polyvinylpyrrolidone are firstly chosen to prepare infrared radiation materials in the form of nanofibers.The experimental ratios and preparation parameters are explored.The experimental results show that the viscosity,conductivity,and surface tension have a decisive influence on the spinnability of sols.The voltage,acceptance distance during the spinning process,and the temperature of calcination have an effect on the formation of the material.The ideal crystal structure is obtained at a calcination temperature of 800°C.The fiber diameter is distributed around 120 nm.The main absorption peaks at 400 cm-1 and 600 cm-1 of the sample are maintained at 100%.Based on the above studies,calcium nitrate is added as raw material.The morphology,elements,crystal structure and infrared radiation properties of lanthanum chromate with different calcium doping amounts are studied.The experimental results show that the calcium element can be doped into the material in stoichiometric ratios,and formed an absorption peak at 900 cm-1.which is enhanced from 30%to 100%with increasing calcium doping.The broad absorption peak at 700?850 cm-1 is also affected,when the doping amount increases from 0.1 to 0.2,the absorption peak here is enhanced from 75%to 90%,and when the doping amount increases from 0.2 to 0.3,the absorption peak is significantly weakened to 30%.The doping has less effect on the intensity of the absorption peak at 600 cm-1,which is basically maintained at 90?100%.The best overall IR absorption is achieved at a calcium doping level of 0.2.Finally,to solve the problem of the brittleness of lanthanum chromate itself,silicon oxide fibers are combined with it as the structural framework to provide the overall flexibility of the composite nanofiber film.The experimental results show that the problem of sample brittleness is solved as the percentage of silicon oxide content increases,and it can withstand 50%flexure experiments.The absorption peaks of the samples were reduced from 77%to 40%at 900 cm-1,from 95%to 50%at 600 cm-1 and from 95%to 90%at 400 cm-1,indicating that the addition of the silicon oxide component affected the overall IR radiation properties of the material.The successful preparation of this flexible lanthanum chromate/silicon oxide composite flexible nanofiber provides a new form for the study of infrared radiating materials and has a broad application prospect. |
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