열방성 액정공중합체의 물성에 미치는 화학구조의 영향

이동진; 최재혁; 김한도; 임무산; 조원호

Polymer(Korea), Vol.18, No.4, 536-542, July, 1994

Export Citation

열방성 액정공중합체의 물성에 미치는 화학구조의 영향

Effects of Chemical Structure on Properties of Thermotropic Liquid Crystalline Copolymers

이동진, 최재혁, 김한도, 임무산, 조원호

초록

단량체 p-acetoxybenzoic acid (p-ABA), terephthalic acid (TPA), low inherent viscosity (IV) poly(ethylene terephthalate) (PET) 및 2,7-diacetoxy naphthalene (2,7-DAN)을 사용하여 여러 조성의 열방성 액정고분자를 제조하여 화학조성이 그 성질에 미치는 영향을 조사하였다. IV가 1.6이상이고 210∼290℃에서 용융가능한 열방성 액정 공중합체를 얻었다. 얻어진 공중합체는 230℃에서부터 최소 320℃까지의 넓은 온도범위까지 nematic mesophase를 보였다. 유리전이온도 및 저장탄성율이 급격히 감소되는 온도는 mesogenic 단위 및 2,7-DAN 함량의 증가에 따라 현저하게 증가하였다.

The thermotropic liquid crystalline copolymers were prepared by melt polymerization using p-acetoxybenzoic acid (p-ABA) and terephthalic acid (TPA) as mesogenic monomers, poly(ethylene terephthalate) (PET) to give a flexible linkage, and 2,7-diacetoxy naphthalene (2,7-DAN) as a dissymmetrical monomer. The composition of these monomers was varied as a means of manipulating thermal and dynamic mechanical properties. The polymers with inherent viscosities near or above 1.6 that were melt processible in the temperature range of 210 ∼ 290℃ were obtained. Highly anisotropic melts were observed indicating the presence of a nematic mesophase. The glass transition temperature increased with increasing contents of mesogenic units and 2,7-DAN. The temperatures at which the storage modulus drastically dropped off increase with increasing mesogenic units and 2,7-DAN.

[References]

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[1] Kim HD, Paul DR, J. Appl. Polym. Sci., 40, 155 (1990)

[2] Kim HD, Paul DR, J. Appl. Polym. Sci., 41, 1843 (1990)

[3] Kim HD, Kang SK, J. Korean Fiber Soc., 27(8), 612 (1990)

[4] Kim EY, Kim DL, Kim HD, J. Korean Fiber Soc., 27(4), 261 (1990)

[5] Cogswell FN, "Recent Advances in Liquid Crystalline Polymer," L.L. Chapoy, Ed., pp. 165-175, Elsevier, London (1985)

[6] Antoun S, Lenz RW, Jin JI, J. Polym. Sci. A: Polym. Chem., 19, 1901 (1981)

[7] Bickel A, Shaw MT, Samulski ET, J. Rheol., 28, 647 (1984)

[8] Hamb FL, J. Polym. Sci. A: Polym. Chem., 10, 3217 (1972)

[9] Hamb FL, U.S. Patent, 3,772,405 (1973)

[10] Jackson WJ, Kuhfuss HF, J. Polym. Sci. A: Polym. Chem., 14, 2043 (1976)

[11] Benson RS, Lewis DN, Polym. Commun., 28, 289 (1987)

[12] Economy J, Storm RS, Matkovich VI, Cottis SG, Mowak BE, J. Polym. Sci. A: Polym. Chem., 14, 2207 (1976)