The Development And Application Of Hydrochromic Material Based On Indolino-Oxazolidine

With the rapid development of economic society,energy shortages,environmental pollution,and the greenhouse effect are becoming more and more prominent.Therefore,energy conservation,emission reduction and environmental protection are receiving more and more attention.Paper,as traditional display media,brings convenience to people’s lives,and it also brings many energy and environmental problems during its manufacturing and use.The rewriteable/reprinted paper can alleviate the above problems to a certain extent for that it can achieve paper recycling.Therefore,in recent years,many studies have been carried out around the development of rewritable paper.The core of rewritable paper is a kind of stimuli-responsive chromic material,which could respond to external stimuli,such as water,light,heat,force,electricity,etc.,and accompanying with a reversible color change process.Among these,rewritable paper based on water-stimulation has many advantages,such as low cost,low toxicity,and high compatibility with existing printing technologies,and is an ideal choice for rewritable material.However,the practical application of hydrochromic rewritable paper is currently in the initial stage of development,and many problems still need to be improved.Therefore,it is important to optimize the existing hydrochromic paper and designing new types of hydrochromic papers.It not only promotes the practical application of existing materials,but also provides new ideas and methods for rewritable materials.In the second chapter,In order to reduce the cost of rewritable paper based on oxazoline hydrochromic dyes,advance its practical application process,inspired by the inverse proton gradient process of stomach under the changes of microenvironment,the precursor of the oxazolidine dye,ring-open form(ROF~+Xs)is directly applied to the preparation of hydrochromic material.We explored the effect of microenvironment on the releasing of proton with reverse proton concentration gradient s of hydrohalide precursor(ROF~+X~-s)in solution and on the solid substrate,respectively.We investigated the effects of microenvironment on proton release and accompanying ring-closing process of hydrohalide precursors(ROF~+X~-s)under inverse proton concentration gradients in solution and on solid substrates,respectively.We have found that both the nucleophilicity of solvent and the concentration of dyes play important roles in the above process.We utilized the property of microenvironment causing the ring-closing under the reverse proton gradient,and replaced the oxazolidine hydrohalide with its alkalized product-the ring-closed form of oxazolidines(RCFs)for the application of water-jet printing rewritable paper(WJRP).Meantime,the effects of preparation solvent and temperature on the hydrochromic effect on WJRP based on ROF~+X~-s were investigated and compared with WJRP based on RCFs.The results show that the former has an advantage in color depth,color displaying speed,and writing retention time.Clear,regular and high-resolution images can be obtained based on the ROF~+X~-s based WJRP via water-jet printing.From the perspective of industrial synthetic preparation,the method proposed in this work can effectively reduce the production cost and promote the industrialization process of WJRP that based on oxazolidine derivatives.In the third chapter,in order to solve the problem that the adjustability of the hydrochromic properties and application of WJRP is limited of physical adsorption preparation method,we tried to modify the hydrochromic dyes on cellulose by chemical grafting,which was further used to construct WJRP.In this"buttom-to-up"construction method,the adjustability of WJRP performance is increased and its application field is also expanded.We loaded the hydrochromic dyes onto cellulose by esterification grafting,and the grafting reaction was confirmed by SEM,FTIR and elemental analysis.The state of the grafted fiber under different environmental conditions was studied to explore its properties and expand its application.The graft fibers are suitable for WJRP after adjusting the supramolecular interaction between the graft fibers.The hydrochromic properties of WJRP based on grafted fibers were then examined.The results show that the loading method of chemical grafting dye makes the color depth of WJRP deeper and prolongs the color retention time,indicating that the hydrochromic properties of WJRP are adjustable.This construction strategy provides new methods and ideas for expanding the application of WJRP.