| Cerium oxide is one of the most important rare earth oxides.As a class of inorganic ultraviolet（UV）shielding agent with excellent UV shielding performance,it has a small forbidden band width,which is conducive to the transition of valence electrons.At the same time,it has the advantages of single crystal type,non-toxic,environmental protection,good electrochemical performance,good thermal stability and low cost,and has been widely used in the fields of catalysts,light-emitting materials and sensors.This paper prepared three different types of nano cerium oxide composite posites and weak photocatalytic activity.The main research contents are described as follows:（1）Under alkaline conditions,in the ethanol solution containing cerium nitrate with ammonia,the reaction of nano cerium oxide rich in hydroxyl surface precipitation,and then 3,4-dihydroxybenzoate ethyl graft modification,3,4-dihydroxybenzoate modified nano cerium oxide（EDHB/Ce O2）,the product can better dispersed in PVC,characterized by UV spectrophotometer and thermal weight analyzer.The results show that the temperature of Ce O2/PVC and EDHB/Ce O2/PVC composite films is increased by 31℃and 6℃respectively compared with pure PVC films.With the UV wavelength in the range of 200–400 nm,the absorbance of EDHB/Ce O2 was increased by 25%compared to Ce O2.Finally,when the molar ratio of EDHB/Ce O2 is 2:1 and the content of EDHB/Ce O2 is 2%,the prepared PVC composite film has the best UV shielding effect.（2）Under alkaline conditions,ammonia was added into a mixture of ammonium and sodium sulfide to precipitate cerium oxide（Bi2S3/Ce O2）,and 3,4-dihydrobenzoate ethyl acid to produce 3,4-dihydrobenzoate modified doped cerium oxide（EDHB/Bi2S3/Ce O2）.The product can be well dispersed in PVC and characterized by UV spectrophotometer and thermogravimetric analyzer.The results show that compared with the temperature of the pure PVC film,the temperature of Ce O2/PVC and Bi2S3/PVC composite films increased by 31℃and 9℃,while the temperature of Bi2S3/Ce O2/PVC and EDHB/Bi2S3/Ce O2/PVC composite films decreased by 3℃and 7℃.With UV wavelengths in the range of 200-400 nm,the absorbance of Bi2S3/Ce O2 and EDHB/Bi2S3/Ce O2 was increased by 13%and 35%compared with Bi2S3,respectively.Finally,within the scope of the study,the doping ratio of Bi2S3/Ce O2 is 5:1,Moreover,when the content of EDHB/Bi2S3/Ce O2 is 2%,the prepared PVC composite film has the best UV shielding effect.（3）Under alkaline conditions,in the ethanol solution containing cerium nitrate hydrate drop ammonia,the reaction of the surface rich nano cerium oxide precipitation,with chitosan to graft modification,generate nano cerium oxide/chitosan composite precipitation（CS/Ce O2）,the product can be effectively dispersed in PVC,by UV spectrophotometer and thermogravimetric analyzer characterization.The results show that the Ce O2/PVC is compared with the pure PVC film.And CS/Ce O2/PVC composite films by 31℃and 17℃,respectively.With the UV wavelength in the range of 200-400nm,the absorbance of CS/Ce O2 was increased by 30%compared with Ce O2.Finally,when the content of CS/Ce O2 is 2%,the prepared PVC composite film has the best UV shielding effect.Figure[40]Table[7]Reference[116]... |
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