The Synthesis And Study Of Liquid Crystalline Polyurethanes

The recent research and development of liquid crystalline polyurethanes were revived, The author put the emphases on the synthesis, the structure, the properties, and (?)e factors that effect the formation of liquid crystalline polyurethanes. The develop-(?)ent tendencies of liquid crystalline polyurethane were foreseen. Thel,4-bis(p-hydroxybenzoates)butanediol(Ⅰ), α , ω -benzoylchloride poly(buty-ne terephthalate)(PHMT) were synthesized by melting transesterification reaction (?)m 1,4-butanediol with methyl p-hydroxybenzoate terephthaloyldichloride,respect-ely. α , ω -phenolic poly(terephthaloyloxybenzoate butylene glycol)(PHTO)was nthesized by 1,4-bis(p-hydroxybenzoates)butanediol and terephthaloyldichloride le block copolyesters(Ⅱ) were synthesized from PHMT and PHTO.The two kinds polyurethanes were synthesized by reaction of 2,4-TDI with (Ⅰ) and (Ⅱ), respectively. Thel,4-bis(p-hydroxybenzoate)phe nylene(Ⅲ) was prepared byl,4-bis(trimethyls-(?)xy)benzenes and p-hydroxybenzoyl chloride. A series of novell,4-bis(p-hydroxya-oxybenzoate)phenylene(Ⅳ) were synthesized by reaction of1,4-bis(p-hydroxybenz-te)phenylene with 3-bromopropanol, 4-bromobutynol, 6-bromohexanol, respectively e liquid crystal polyurethanes were prepared by condensation ofl,4-bis(p-hydroxy-;oxybenzoate)phenylene with HDL MDI, 2,4-TDI, respectively. thermotropic liquid (?)stalline properties, thermal stability, the melting point(T_m) and the isotropization int(Ti) of the synthesized polyurethanes were characterized by DSC, POM, the stru-(?)re of polyurethanes was examined by IR, the crystal type was examined by X-ray fraction. It showed that all of the polyurethane polymers exhibited thermotropic uid crystalline properties between the melting point and the temperature, the asition temperature(T_m and Ti) decreased with an increase in the length of the...