Azobenzene-modified pullulan with different substitution degrees were prepared by changing feed molar ratio of 4-phenylazophenyloxybutyrate acid to pullulan. The structure of the modified pullulan were characterized by 1 H NMR and FTIR spectroscopies. The substitution degrees were determined by elemental analysis and UV-Vis spectra. Photochromism property in solution was investigated by UV-Vis spectroscopy, isomerization behavior of azobenzene moeties of polymer under irradiation at 350 nm is obvious. After 4 min irradiation, trans isomer of sample 3 change into cis isomer completely. Furthermore, unlike pullulan, which is soluble only in H2O or DMSO, the solubility of these products in common organic solvent increased greatly.
A kind of high Fluorine-containing poly(aryl ether) without side reaction was synthesized in a two-step synthesis. Its structure was confirmed by FTIR, 1H NMR and 19F NMR. The polymer shows an excellent thermal stability, good solubility, low water absorption, low dielectric constant and low refractive index. Flexible and transparant thin film can be easily obtained by compression moulding or solution casting. The polymer would be a promising material used for microelectronics and waveguide devices.
