노출조건에 따른 전분 완충재의 물리적 성질의 변화

임대영; 임승순; 한정석

Polymer(Korea), Vol.19, No.4, 469-477, July, 1995

Export Citation

노출조건에 따른 전분 완충재의 물리적 성질의 변화

The Changes of Physical Properties of Starch Loose-fill According to Exposure Condition

임대영, 임승순, 한정석

초록

동방향 회전형 이축스크류식 압출기를 사용하여 옥수수전분과 폴리비닐알콜을 주원료로 하는 완충재를 제조하였다. 완충재의 물리적 성질은 셀의 크기 분포 및 셀벽 성분의 밀도에 크게 영향을 받음을 알 수 있었다. 반면에 전분의 종류에 따른 전분 완충재의 물리적 성질 차이는 관찰할 수 없었다. 동일한 압출조건에서 전분의 투입속도(g/min.)가 증가하면 셀의 크기가 비교적 균일하고 표면 요철이 적은 전분 완충재를 얻을 수 있었다. 또한 투입량이 증가되면 전분 완충재의 팽창비가 커지는 반면에 겉보기밀도는 작아짐을 알 수 있었다. 또한 압축강도가 커지고 구조완화에 따른 수축정도가 작아짐을 보이는데, 이는 투입속도가 증가함에 따라 셀벽의 순수밀도가 증가했기 때문으로 생각할 수 있었다. 전분의 투입속도가 큰 완충재 (No. 2)의 경우는 고온 다습한 환경에서도 수분의 흡수량이 다른 전분 완충재들에 비해 크지 않았으며, 물성이 크게 변화하지 않음을 알 수 있었다. 또한 선적(船積)시험시 폴리스티렌 완충재에 필적할 만한 물성을 가지고 있음을 알 수 있었다. 전분 완충재는 물에서 완전히 분산되어 완충재로서의 형태를 완전히 잃어버림을 관찰할 수 있었다.

Protective loose-fill was prepared with corn starch and poly(vinyl alcohol) as major components using intermeshing corotating twin-screw extruder. Physical properties of loose-fill greatly depended on the distribution of cell size and the density of cell wall material. However, the dependency on the kind of starch was negligible. The loose-fill with even distributed cell size and less irregular surface was obtained when the feed rate(g/min.) increased at same extrusion condition. The compressive strength increased and the degree of shrinkage via structural relaxation decreased, which was assumed to be due to the increase of true density of cell wall. The loose-fill with high feed rate (No. 2) had the lower water absorption and change of properties. The shipping test showed that the loose-fill had comparable properties with polystyrene loose-fill. The loose-fill completely dispersed and then lost its shape when it was on water.

Keywords:loose-fill;corn starch;poly(vinyl alcohol);structural relaxation

[References]

Lacourse NL, U.S. Patent, 4,863,655 (1989)
Neumann PE, U.S. Patent, 5,185,382 (1993)
Altiere PA, U.S. Patent, 5,153,037 (1992)
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[1] Lacourse NL, U.S. Patent, 4,863,655 (1989)

[2] Neumann PE, U.S. Patent, 5,185,382 (1993)

[3] Altiere PA, U.S. Patent, 5,153,037 (1992)

[4] Altieri PA, Lacourse NL, "Starch-based Protective Loose Fill Material," in Proceedings of Corn Utilization Conference IV, June 24-26 (1992)

[5] Lim DL, Submitted in Biotechnol. Prog., Jan. (1995)

[6] Shogren RL, Jasberg BK, "Aging Properties of Extruded High Amylose Starch," in Abstracts of Conference of Bio/Environmentally Degradable Polymer Society, August 19-21, Chicago, Illinois (1993)

[7] "Developments of Biodegradable Polymers by Modification of Starch," Final report, Hanyang Univ., Sept. (1994)

[8] Mercier et al., "Structural Modification of Various Starches by Extrusion-Cooking with a Twin-screw French Extruder," in Polysaccharides in Food, eds. by J.M.V. Blanchard and J.R. Mitchell, p. 152-170, Butterworths, England (1979)

[9] Galliard T, Bowler P, "Morphology and Composition of Starch," in Starch: Properties and Potential, Critical Reports on Applied Chemistry, vol. 13, ed. by T. Galliard, John Wiley & Sons, Great Britain (1987)