열방성 주축 액정 폴리 에스터의 Isotropic상에서의 비평형 Excess Order와 이들과 Banded Texture와의 상관 관계에 대한 연구

제갈종건; 이규호; Blumstein A

Polymer(Korea), Vol.18, No.4, 457-462, July, 1994

Study on the Non-Equilibrium Excess Order in the Isotropic Phase and Its Correlation with Banded Textures of the Thermotropic Main Chain Liquid Crystalline Polyester

제갈종건, 이규호, Blumstein A

초록

4,4'-Dihydroxy-α-methyl stilbene을 mesogen으로 이용하여 제조된 상대적으로 높은 분자량(Mn=56,500g/mo1)을 가진 주사슬 열방성 폴리에스터를 이용해서 isotropic phase에서의 잔여 nematic order를 연구하였다. Isotropic phase에서 냉각 되면서 다시 생성되어지는 banded texture의 재현성(memory 효과)을 연구 하였으며 이와 Isotropic phase에서의 잔여 nematic order와의 상관관계를 또한 연구 하였다. 고분자 샘플들은 isotropic phase인 247℃에서 일정시간동안 annealing 후 빠른 속도로 0℃까지 냉각되어졌다. 그 고분자의 T_n/i, T_k/n, ΔH_n/i, 그리고 ΔH_k/n들은 annealing 시간이 길어짐에 따라 감소 하였다. 그러나 이들 감소한 T_n/i, T_k/n, ΔH_n/i, 그리고 ΔH_k/n들은 nematic mesophase에서 10시간동안 annealing함으로써 원상복귀 되었다. Banded texture도 isotropic phase에서 사라졌다가 냉각 도중에 다시 나타났다.

The excess nematic order in isotropic phase of the thermotropic liquid crystalline polymer was studied with a polyester based on the 4, 4'-dihydroxy-α-methylstilbene as mesogen with a relatively high molecular weight(Mn=56,500g/mo1). The reproducibility (memory effect) of the banded texture on the cooling from the iostropic phase was studied and correlated with excess nematic order in isotropic phase. The polymer samples were annested at the isotropic phase(247℃), followed by quick cooling to 0℃, for different periods of time. The T_n/i, T_k/n ΔH_n/i and ΔH_k/n of the polymer were decreased with the increasing annealing time. However, the decreased T_n/i, T_k/n ΔH_n/i of the polymer were recovered by the annealing at the nematic mesophase of the polymer for 10 hours. The banded texture of the polymer sample, disappered at the isotropic phase, also reappeared on the cooling.

[References]

Feijeo JL, Ungar G, Keller A, Persec V, Polymer, 31, 2019 (1990)
Donald AM, Viney C, Windle AH, Polymer, 24, 155 (1983)
Nishio Y, Yamane T, Takahashi T, J. Polym. Sci. B: Polym. Phys., 23, 1053 (1985)
Bedford SE, Windle AH, Polymer, 31, 616 (1990)
Liu X, Shen D, Shi L, Xu M, Polymer, 31, 1987 (1990)
Jegal JG, Lin CH, Blumstein A, Polym. Prepr., 32, 215 (1991)
Jegal JG, Blumstein A, in preparation

[1] Feijeo JL, Ungar G, Keller A, Persec V, Polymer, 31, 2019 (1990)

[2] Donald AM, Viney C, Windle AH, Polymer, 24, 155 (1983)

[3] Nishio Y, Yamane T, Takahashi T, J. Polym. Sci. B: Polym. Phys., 23, 1053 (1985)

[4] Bedford SE, Windle AH, Polymer, 31, 616 (1990)

[5] Liu X, Shen D, Shi L, Xu M, Polymer, 31, 1987 (1990)

[6] Jegal JG, Lin CH, Blumstein A, Polym. Prepr., 32, 215 (1991)

[7] Jegal JG, Blumstein A, in preparation