Preparation And Properties Of Chitosan Modified Sepiolite-baesd Hybrid Pigments

Organic pigments have attracted widespread attention due to their bright colors,light tones,and various types.They can be widely used in industrial coatings,printing inks,textiles,plastics and other fields.Although organic pigments have many advantages,they also have some disadvantages,such as poor weather fastness and thermal stability,low light resistance,which limit the development and industrial application of organic pigments.Therefore,it is necessary to find ways to improve its thermal stability,weather resistance and ultraviolet stability,so as to improve the application performance of organic pigments.In this paper,organic-inorganic hybrid pigments were used to overcome the shortcomings of organic pigments.Chitosan-modified sepiolite is used as an inorganic material to prepare organic-inorganic hybrid pigments.The preparation conditions of hybrid pigments were discussed.The structural characteristics and formation mechanism of hybrid pigments were investigated.And the resistance to acids,alkalis,organic reagents,thermal stability and light stability of organic-inorganic hybrid pigments before and after formation were studied.In this paper,chitosan?CTS?modified sepiolite is used as an inorganic material to prepare hybrid pigments by absorbing organic dye acid red 73?AR 73?and coating organic pigment?pigment red 21?.The first method is to uniformly adsorb the organic dye Acid Red 73?AR73?around the inorganic material to form hybrid pigment.The effects of the amount of CTS,the concentrations of acetic acid?HAc?and the p H of AR73 solution on the performance of CTS-sep were investigated and the hybrid pigment?CTS-sep/AR73?which could immobilize the most AR73 was obtained.In order to enhance the stability of the hybrid pigment,the CTS-sep/AR73@Si O₂ pigment was prepared by CTS-sep/AR73 coated with a layer of Si O₂.In the second method,CTS-sep was used as an inorganic material,and the Pigment Red 21 was used to coat the inorganic materials to prepare hybrid pigments.In order to improve the stability of the hybrid pigment,a layer of silica coating was prepared.The ratio of the inorganic material to the Pigment Red 21 and the concentration of TEOS were discussed,thereby obtaining a coated hybrid pigment having a chromaticity close to that of the original Pigment Red 21.The mechanism of formation of hybrid pigment by two methods can be obtained by characterization analysis.CTS-sep/AR73 hybrid pigment was formed by anion-cation electrostatic interaction and hydrogen bonding interaction between CTS-sep and AR73 molecules.The second hybrid pigment is formed by electrostatic interaction with the hydrogen bonding between CTS-sep and Pigment Red 21.The two kinds of hybrid pigments were coated with a layer of silicon dioxide on the surface of the hybrid pigments with the action of cetyltrimethylammonium bromide?CTAB?surfactant which improved the stability of the hybrid pigments.In addition,the stabilities of hybrid pigments were tested by acid,alkali,and organic reagents.Using thermal gravimetric analysis and ultraviolet spectrum analysis to test their thermal and light stability.It has been proved that the stabilities of hybrid pigments and coated hybrid pigments are improved,the stability of coated hybrid pigments is better.The thermal stability of CTS-sep/AR73@Si O₂ can reach 220?,which is higher than that of CTS-sep/AR73.The heat resistance of the CTS-sep/Pigment Red 21 hybrid pigment is 40?higher than that of the Pigment Red 21 and the heat resistance of the coated hybrid pigment is 250?which is 30?higher than that of the hybrid pigment before coating.