Study On The Preparation Of Reversible Thermochromic Material Hybrid Modified Silica Sol System And Its Application

Some compounds or mixtures, whose color can be changed by heating or cooling, are known as thermochromic material. Nowadays, the electron donating-accepting reversible thermochromic materials are widely used in textile finishing. Despite this, the fibers barely have affinity with this kind of thermochromic materials, its application are mainly accomplished though microencapsulation and adhesives. This original technical can't meet requirements. On one hand, the wall of microencapsule is common used organic material which both has poor chemical stability and mechanical stability, so it is unable to protect the thermochromic material. On the other hand, using the adhesives to adhere the microencapsule to the textile brings hard handfeel and uneven dyeing. The sol-gel technology can avoid these disadvantages and it's a new trend. Combining with the feature of electron donating-accepting reversible thermochromic material and sol-gel technology, research was carried out to extend their application. The objective is to realize thermochromic finishing combined with sol-gel technology. This thesis is consisted of three sections as the following:Firstly, reversible thermochromic materials were prepared, by using crystal violet lactone as electron acceptor, bisphenol-s as electron donator, cetanol as reaction medium respectively. Their thermochromic processes were analyzed by DSC, and the thermochromic mechanism of reversible thermochromic materials was discussed by FT-IR spectrum, and NMR from the molecular thermalmotion of reaction medium. Thus inferred that the lactonic ring on crystal violet lactone molecule didn't open during the thermochromatic material's color-changed process, it was only attributed to the changes in the density of electron cloud of chemical bonds in lactonic ring which was caused by bisphenol-s. Heat discoloration temperature of this material from 35℃to 50℃, and it was in accordance with melting progress of cetanol showed by DSC. When cetanol, acted as reaction medium, produced phase change under high temperature, the internal thermal motion of their molecules became ever faster, and it destroyed the intermolecular interactions between crystal violet lactone and bisphenol-s, which led to thermochromism.Secondly, we investigate the infuences of dosages of water, co-solvent (ethanol), catalyst(hydrochloric acid), modifier (γ-glycidoxypropyltrimethoxysilane and phenyltriethoxysilane), reaction temperature and time on the properties of the obtained silica sol (size of colloidal particle, stabilization time and viscosity) by single factor experimentation. The structure of tow kind of modified silicon sols were characterized by FT-IR and DSC. The results showed that:modifierγ-glycidoxypropyltrimethoxysilane(GPTMS) brought higher stability and flexibility to the thin gelatin film, modifier phenyltriethoxysilane (PhTES) brought higher hydrophobicity to the thin gelatin film.Thirdly, we investigate the influences of dosages of thermochromic materials, modifier (γ-glycidoxypropyltrimethoxysilane and phenyltriethoxysilane), curing temperature and time on the properties of treated textile (mechanical properties, reversible thermochromism performance, handfeel, color fastness). The results showed that:(1)The dosages of thermochromic materials affected the reversible thermochromism performance of treated textile, and it were limited by the package ability of modified gel silicon film. (2)Curing process affected the gelation of modified silica sol, the silica sol modified by PhTES was more likely to gelatinize. (3) Textile treated by modified silica gel finishing liquor had better both wet and dry rubbing fastness, and modifier GPTMS brought better handfeel and mechanical properties.