Glucomannan의 유변학적 성질에 관한 연구

김남희; 김경이

Korean Journal of Rheology, Vol.5, No.2, 161-169, December, 1993

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Glucomannan의 유변학적 성질에 관한 연구

A Study on the Rheological Properties of Glucomannan

김남희, 김경이

초록

Glucomannan(G.M.)은 Amorphophallus Konjac C. Koch의 tuber로부터 분리되었고, 이 G.M.은 다시 침전제로 메탄올을 사용하여 4단계로 분별되었다(F.1, F.2, F.3, F.4). 각 분별물들을 농도에 대하여 환산점도를 도시하여 고유점성도값을 구한 결과, 분자량이 높은 분별물이 낮은 분자량의 분별물에 비하여 직선으로부터 벗어남을 보였다. Low shear viscometer로 G.M. 용액의 viscosity를 측정하였고 농도와 zero shear specific viscosity의 logarithm을 도시한 결과 inflection point를 나타내었다. 이것은 G.M. 분자들의 coil overlap의 시작에서 기인한 것이고 묽은 용액에서 진한 용액으로의 전이행동은 임계농도, C^*=4/[ ]에서 일어났고 이때의 zero shear specific viscosity는 10을 나타내었다. 또한 specific viscosity는 묽은 용액에 대해서는 C^1.4로써 변화하였고 진한 용액에서는 C^3.0으로 변화하였다. G.M.의 고체상태에 대한 유전성( ', ")과 점탄성(C', C")계수들을 액체질소 온도에서부터 150℃ 온도범위에 걸쳐 4단계로 film을 건조시키면서 10 Hz에서 측정하였다. G.M. film의 유전성과 점탄성의 허수부분은( ",C"), -100℃에서 peak를 나타내었고 이 peak는 hydroxy methyl기들의 회전 운동에서 생겨난 것이다. 건조시키지 않은 상태의 G.M. film의 유전성과 점탄성의 허수부분의 값들은 -50℃에서 물 분자의 운동에 의하여 생긴 peak를 보였다.

Glucomannan, isolated from the tuber of Amorphophallus Konjac C. Koch, was washed by methanol and was fractionated into four fractions using methanol as a precipitant. Intrinsic viscosity was determined by Ubbelohde viscometer. The fraction of higher molecular weight showed a deviation from linerity in the plot of reduced viscosity against concentration with comparison to the fraition of lower molecular weight. The viscosity of glucomannan solution was observed by a low shear viscometer. The plot of the logarithm of the zero shear specific viscosity against the logarithm of the concentration of the glucomannan solution showed an inflection point. It was attributed to the commencement of the coil overlap of glucomannan molecules. The transition from dilute to concentrated solution behaviour occured at a critical concentration C^*=4/[η], which corresponds to zero shear specific viscosity (η_sp)=10. η_sp varied as C^1.4 for dilute solutions as C^3.0 for concentrated solutions. Dielectric and viscoelastic coefficients were observed at 10 Hz from the liquid nitrogen temperature to 150℃ for glucomannan in solid state. The imaginary part of dielectric (ε") and viscoelastic (C") properties of glucomannan showed a peak at -100℃ and this peak was caused by rotational motion of hydroxymethyl groups. The value of " and C" for humid glucomannan film showed a peak at -50℃ and this peak was attributed to the commencement of molecular of frozen bound water molecule.

Keywords:glucomannan;intrinstic viscosity;zero shear specific viscosity;coil overlap;fractionation;shear rate;shear stree;film;dielectric constant;viscoelastic constant

[References]

Kato K, Matsuda K, Agric. Biol. Chem., 33, 1446 (1969)
Maeda M, Shimahara H, Sugiyama N, Agric. Biol. Chem., 44, 245 (1980)
Tsuji C, J. Colloid Agric. Tokyo Imp. Univ., 2, 103 (1895)
Mayeda M, Mitteil. Med. Gesellsch. Tokyo, 25, 518 (1911)
Nishida K, Hashima H, J. Dep. Agric. Kyushu Imp. Univ., 2, 277 (1930)
Smith F, Srivastava HC, J. Am. Chem. Soc., 81, 1715 (1959)
Kato K, Matsuda K, Agric. Biol. Chem., 37, 2045 (1973)
Maekaji K, Agric. Biol. Chem., 38, 315 (1974)
Watase M, Nishinari K, Rheol. Acta, 22, 580 (1983)
Fukada E, Kaibara M, Thrombosis Res. Suppl. II, 8, 49 (1976)
Gralessley WW, The Entanglement Concept in Polymer Rheology, Advances in Polymer Science, Vol. 16, Berlin, Springer-Verlag (1974)
Morris E, Culter R, Ross-Murphy AN, Carbohydr. S.B., Rees, D.A. Polym., 1, 5 (1981)
Nishinari K, Fukada E, J. Polym. Sci. B: Polym. Phys., 18, 1609 (1980)
Nishinari K, Horiuchi H, Fukada E, Pep. Prog. Polym. Phys. Jpn., 23, 759 (1980)
Nishinari K, Shibuya N, Kainuma K, Makromol. Chem., 186, 433 (1985)
Nishinari K, Tsutsumi A, J. Polym. Sci. A: Polym. Chem., 22, 95 (1984)

[Referenced By]

[1] Kato K, Matsuda K, Agric. Biol. Chem., 33, 1446 (1969)

[2] Maeda M, Shimahara H, Sugiyama N, Agric. Biol. Chem., 44, 245 (1980)

[3] Tsuji C, J. Colloid Agric. Tokyo Imp. Univ., 2, 103 (1895)

[4] Mayeda M, Mitteil. Med. Gesellsch. Tokyo, 25, 518 (1911)

[5] Nishida K, Hashima H, J. Dep. Agric. Kyushu Imp. Univ., 2, 277 (1930)

[6] Smith F, Srivastava HC, J. Am. Chem. Soc., 81, 1715 (1959)

[7] Kato K, Matsuda K, Agric. Biol. Chem., 37, 2045 (1973)

[8] Maekaji K, Agric. Biol. Chem., 38, 315 (1974)

[9] Watase M, Nishinari K, Rheol. Acta, 22, 580 (1983)

[10] Fukada E, Kaibara M, Thrombosis Res. Suppl. II, 8, 49 (1976)

[11] Gralessley WW, The Entanglement Concept in Polymer Rheology, Advances in Polymer Science, Vol. 16, Berlin, Springer-Verlag (1974)

[12] Morris E, Culter R, Ross-Murphy AN, Carbohydr. S.B., Rees, D.A. Polym., 1, 5 (1981)

[13] Nishinari K, Fukada E, J. Polym. Sci. B: Polym. Phys., 18, 1609 (1980)

[14] Nishinari K, Horiuchi H, Fukada E, Pep. Prog. Polym. Phys. Jpn., 23, 759 (1980)

[15] Nishinari K, Shibuya N, Kainuma K, Makromol. Chem., 186, 433 (1985)

[16] Nishinari K, Tsutsumi A, J. Polym. Sci. A: Polym. Chem., 22, 95 (1984)