Synthesis And Performance Of Near Infrared Reflective Organic Dyes

Under the environment of the strong sunshine, the light may cause object’ssurface temperature arise, we usually need to consume energy to cool. If the objectitself can reflect the light of the solar radiation energy into the atmosphere, we canreduce surface temperature without external energy. We can use the pigments (or dyes)or coating that have the function of reflecting the sunshine erergy instead of thetraditional paint, one of them is near infrared reflected function pigments (or dyes),such pigments or dyes can reflect the light of near infrared region that occupy a largerproportion of the solar energy to keep the object’s surface and interior cool.There are many kinds of available near infrared reflection commercial dyes, butthey mostly belong to inorganic class, which contain the heavy metals are toxic,normally makes them not environmentally friendly, and our research is near infraredreflected organic dye, perylene dyes is selected to be the subject investigated, theyhave the unique physical and chemical properties of organic dyes, and has the specialproperties of the near infrared reflecting.We designed and synthesized a series of perylene dyes, and make a performancecomparison of near infrared reflecting with some kinds of commercial pigments afterdispersed into polymer. The key work is to study the reflecting mechanism andinfluencing factors, including particle size, distribution and composition of dye, theelectronic structure of different substituent, crystallinity and other factors.The experimental results show that, in the research of five perylene dyes P1, P2,P3, P4, BZP and initial raw materials PTCA, the derivativesP1-P4show betterperformance of the near infrared reflected, and the BZP is poor, taken together, theorder of near infrared reflected performance is PTCA>P2> P1>P4>P3> BZP.Compared to the other pigments, we found that TiO2showed the strongest reflectingperformance, a kind of AZO dye followed, and the reflecting ability of carbon black isthe most weak. We also found it by studying the factors influencing the near-infrared reflection, particle size and particle distribution have great influence to the reflection,with the decrease of dye particle size and distributed evenly, the samples’ nearinfrared reflected performance gets better, but the state of particles is not the onlyfactor, and other influencing factors is common, such as the degree of crystallinity ofthe sample and the electronic structure of molecules, through the theoretical researchof different derivatives we found that.