Thermotropic liquid crystalline polyesters and copolyesters based on the 4,4'-dihydroxy-α-methyl stilbene(DYS-00, DYS-50, DYS-70) or 4,4'-dihydroxy-2,2'-dimethyl azoxybenzene(AZA-9 and DDA-9) were processed to obtain films and fibers; The films of these polymers were prepared by the casting of polymer solutions in chloroform and fibers of them were prepared by the melt spinning in their mesophases. The mechanical properties of these films and fibers such as moduli and tenacity were studied. The variation in the moduli of the films as a function of elongation ratio was studied; The moduli of films were increased with elongation ratio. The effect of the temperature on the moduli of the films and fibers was also studied; The moduli of unoriented films decreased in relatively large scale with increasing temperature, but those of oriented films and fibers did not decrease much even above glass transition temperatures.

4,4'-Dihydroxy-α-methyl stilbene이나 4,4'-dlhydroxy-2,2'-dimethyl azoxybenzene을 이용하여 합성된 열방성 주축 액정 Polyester와 Copolyester들을 이용하여 이들의 Film과 Fiber들을 제조 하였다. 이때 Film은 액정 고분자 용액을 Casting 해서 제조 하였으며, Fiber는 액정 고분자를 Mesophase에서 녹여서 하는 Melt spinning 방법을 이용해서 제조 하였다. 이들 제조된 Film과 Fiber들의 기계적 성질들(Modulus, Tenacity)을 연구하였다. Elongation ratio에 따른 Film들의 Modulus들을 연구 하였으며 이때 Film의 Modulus는 Elongation ratio에 따라서 증가하였다. Film과 Fiber들의 Modulus가 온도에 따라서는 어떻게 변하는가 또한 연구하였다. Orientation 되지않은 Film의 Modulus는 온도증가에 따라서 큰 폭으로 감소하는데 반해서 Orientation이 된 Film이나 Fiber의 Modulus는 유리전이 온도 이상에서도 크게 감소하지 않았다.

Keywords: liquid crystal; film; fiber; mechanical properties