一种新型侧链聚酰亚胺的合成与性质研究

novel diamine 4-[(4′-octyloxyphenoxy)carbonyl]phenyl-3′′,5′′-diaminobenzoate (OCDA) that contain octyloxy moiety was synthesized through esterifition, selective hydrolization of ester bonds, hydrogenation deoxidize,. The structure was confirmed by FTIR and 1HNMR. A series of polyimides with octyloxy moiety capped side-chains were synthesized from one-step-method. The properties of the PIs, such as the inherent viscosity, aggregation structures, thermal character, and the pretilt angles, were studied. All of the inherent viscosity of PI-OCDAx were only about 0.3, and decreased with increasing of the rate of OCDA in diamines. Crystal was found in all the PI-OCDAx films by POM, what’s more, it was grain crystal in PI－OCDA0.2～OCDA0.8, and needle piece crystal was found in PI-OCDA1.0. Tg of PI-OCDA0.6 and PI-OCDA1.0 were 159℃ and 174℃ corresponding. PI-OCDAx showed three-step weight loss in the range of 50-700℃, and the set up temperature is 230℃. The pretilt angles of Liquid crystal cell assemble with PI-OCDAx had obvious difference before and after rubbing, what illuminated rubbing was very importance for the generation of pretilt angle.