| Fluorane thermochromic materials,as the third generation of thermochromic materials,have the advantages of rich colors,high color contrast,simple processing,good reversibility,controllable temperature range,etc.They are widely used in camouflage,information display,temperature indication,intelligent windows,sensing and color changing clothing.However,fluorane thermochromic materials are generally three component thermochromic materials,which are difficult to change color at the phase transition temperature and have a color change hysteresis;Secondly,when fluorane thermochromic materials are applied to textiles,microcapsules are usually encapsulated,and then the microcapsules are finished on the fabric with the aid of adhesives and other additives,which will further reduce the temperature sensing ability of the core material,leading to an increase in the discoloration time and an increase in hysteresis.In this paper,boron nitride(BN)nanoparticles are used as thermal conductive materials,and BN nanoparticles are arranged on the surface of the microcapsule shell and the thermochromic fabric.A highly sensitive thermochromic fabric with short color change time and narrow color change range is obtained.The specific work is as follows:1.Boron nitride nano sheets(BNNS)were prepared by high-temperature oxidation and ultrasonic cell pulverization,and BNNS doped fast response thermochromic fabric was prepared by screen printing technology.The effects of BNNS content on color,color change and fastness were studied.The results showed that the doping of BNNS would reduce the K/S value of the thermochromic fabric,resulting in light color effect;When the content of BNNS is2%,the thermochromic fabric has faster color change time(8 s)and recolor time(13 s);Narrow discoloration temperature range is 31.4～37.2 ℃ and polychrome temperature range is28.8～25.4 ℃;And excellent cycle stability(>200 times),rubbing and washing fastness(≥ 4levels).2.Orange-red fluorane dye,bisphenol A and hexadecanol were used to synthesize reversible thermochromic materials(TM)in proportion,and BN/MF resin hybrid shell thermochromic microcapsules(BTMs)were prepared by in situ polymerization.The preparation process of BTMs was explored: the mass ratio of emulsifier to aqueous phase system was 2%;the emulsification time was 20 min;p H was 4.5;and the core shell ratio was2:1.OM and SEM proved that BN nanoparticles were successfully doped in the shell polymer of BTMs.The influence of BN content on the color change response speed of microcapsules was studied and analyzed.When BN content was 5%,the color change time of thermochromic microcapsules was 10 s,the color change time was 6s,the color change temperature range was41.9～46.5 ℃,and the color change temperature range was 41～36.5 ℃.Compared with the microcapsules without BN doping,the thermochromic time of the microcapsules was shortened by 9 s and 5 s,respectively 47.4% and 45.5%;The color change temperature range and the color reproduction temperature range are shortened by 1.4 ℃ and 1.1 ℃ respectively.3.Through screen printing technology,the self-made BN/MF resin hybrid shell thermochromic microcapsule was applied to fabric printing to prepare the thermochromic fabric(BTF).The color and discoloration properties of the fabric were analyzed.It was found that the larger the K/S value of the microcapsule,the larger the K/S value of the fabric,and the darker the color.When BTF-5 fabric is prepared with BTMs with 5% BN content,the color change time of BTF-5 is 12.5 s,and the recolor time is 7 s.Compared with the color change fabric(BTF-0)prepared by BTMs with BN content of 0,the color change time of BTF-5 is shortened by 40.5%,and the re color time is shortened by 44.0%;The thermochromic range is shortened by 1.7 ℃,and the polychromic range is shortened by 1.5 ℃.That is,the thermochromic fabric with fast response can be prepared by doping BN on the shell of the microcapsule.However,compared with thermochromic microcapsules,thermochromic fabrics have longer color change time and wider color change range. |
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