With Polar Side Groups Of Poly-phenylene Benzoxazole Synthesis And Characterization,

Two Polyparaphenylene benzobisoxazole (PBO) with high lateral polarity chain were designed and synthesized in order to improve their solubility, fusing performance as well as optical performance.Firstly, three monomers of diaminodihydroxybenzenedihydrochloride (DADHB) and2-(4, 5, 6, 7-Tetrachloro-1, 3-dioxo-1, 3-dihydro-isoindol-2-yl)-terephthalicacid (TCTA) and 2-(4,5,6,7-Tetrafluoro-1,3-dioxo-1,3-dihydro-isoindol-2-yl)-terephthalic acid(TFTA) were synthesized.Their structures were confirmed by FT-IR,¹HNMR and ¹³CNMR. The structures of three polymers-PBO, PBTCO and PBTFO were confirmed by FT-IR.Secondly, extracted the PBTCO and PBTFO in DMF, the PBTCOD and PBTFOD which can be solved in DMF were obtained. Their thermal properities were studied by DSC and polarizing optical microscope (POM). Melting point can be seen from the DSC curves of PBTCOD and PBTFOD. The birefringence of liquid crystalline state was observed when heating the polymers above their melting temperature.High molelular weight of PBTCOM and PBTFOM which can not be dissolved in DMF was measured by viscosimetry. The result indicated that they could be applied in the future.Thermal analysis indicates that both PBTCOM and PBTFOM have high decomposition temperature. PBTCOM and PBTFOM showed higher fluoscence intensity comparied with PBO, however, concentration quench effect is still strong. Molecular weight of PBTCOD and PBTFOD were measured by GPC with the results of high molecular weght and low molecular weight distribute. Thermal analysis demonstrates that their decomposition temperature of 5% drops a lot comparied with PBO, however, their decomposition temperature are still above 300 centigrade. PBTCOD and PBTFOD have strong fluoscence intensity and weak concentration quench effect. Quanta efficiency of PBTCOD and PBTFOD were 0.51 and 0.18, respectively. A new emission peak around 630nm is appeared in the case of PBTFOD. The intensity of this peak is increased when the concentration of the polymer increase. As a result, the concentrated solutions of the polymer show a near white emission. Its solid films have the same phenomena, implying the PBTFOD can be used as single polymer material exhibiting white light emission.