The Synthesis And Photochromism Study Of The Graft Copolymers Of Starch And AZO-Dyes

This thesis consist of the following three parts:Part I: Aromatic Azo Polymers and Their Optical ApplicationsDuring the last 10 years, a lot of new optical phenomena has emerged. This review concentrates on the resent developments in aromatic azo polymer research. The structure and properties of aromatic azo compounds are briefly presented. Basic mechanism and experimental methods are also reviewed. The large number of potential applications as reversible optical data storage has stimulated a great deal of experimental and theoretical work. The interesting optical properties include light-induced phase transition of LCP, command surfaces, light-induced birefringence and dichroism, second-order nonlinearity and light-induced surface relief gratings, etc. The potential applications of these properties are also discussed, and the difficulties that stand in the way to realistic applications are also listed. Part II: The Synthesis and Structural Characterization of Starch-Azo dyes Graft CopolymersThe graft copolymerization of azo-dyes and potato starch were carried out using APS-NaHSO3 as initiation system, Sodium dodecyl benzene sulfate as emulsifier. The effects of concentration of initiators, reaction temperature, reaction period, concentration of monomer has been investigated. When the concentration of initiator was 6mmol/l, the monomer concentration was 0.35mol/l, the reaction temperature and reaction period choosed as 40 and 3h respectively, the optimum G% and E% were obtained. The evidence and characterization of the graft copolymers has been researched by means of FTIR spectroscopy, X-ray diffraction analysis, thermogravimetry analysis (TGA) and DSC. Part III: Photochromism Behavior of copolymers of Starch and Azo-dyes insolutions and in thin filmThe reversible photoisomerization and the thermal isomerization of 9 copolymers of azo-dyes and starch were investigated in solutions and dispersed in thin PMMA film. The effects of solvent, substituent effects, irradiance of different power lamp, temperature during thermal isomerization were also investigated. The results observed were: in solvents of different polarity, the absorbance of max of azo and the rates of thermal isomerization were different; rates of thermal isomerization of some para-donor/para'-acceptor substituted azo were faster than those didn't have this substituted type; the higher power of lamp induced the azo reached equilibrium more quickly; during thermal isomerization, the rates increased with the increasing of temperature.