전분충전 LDPE복합수지의 기계적 물성 : 물리적 표면개질 효과

유영태; 김동국

Polymer(Korea), Vol.18, No.4, 602-612, July, 1994

Export Citation

전분충전 LDPE복합수지의 기계적 물성 : 물리적 표면개질 효과

Mechanical Properties of Starch Filled LDPE Composite Filmes : Effect of Physical Modification of Starch Surface

유영태, 김동국

초록

미처리 전분충전 LDPE(저밀도폴리에딜렌) 필름의 기계적 물성을 측정한 결과 탄성율 (10%신율 기준)은 전분함량(9∼23wt%)의 증가에 따라 증가하는 경향을 보이고, 인장강도는 LDPE에 비해 10% 정도의 감소를 나타내었다. 반면, 파단신율은 전분함량 9wt%에서 LDPE의 20%로 감소하였다. 계면활성제 및 ethylene oxide와 capro;actone의 블록 공중합체를 전분의 0.5-l0wt% 범위에서 사용하여 전분표면을 코팅하였다. 이중 4 가 암모니움 양이온계나 친유성 비 이온계 계면활성제 혹은 고분자량 블록 공중합체로 표면처리된 전분을 LDPE와 혼합하였을 때 전분·9wt%함유 복합체의 파단신율은 550∼750%, l7wt%에서는 300∼400%로 미처리 전분에 비해 크게 향상되었다. 이와 같은 결과는 이들 소재들이 혼합시 효과적으로 전분의 표면에너지를 낮추어 분산성이 개선되었고 인장변형시 생성된 공소의 형태안정성으로 균열전파가 지연되기 때문인 것으로 해석된다.

Mechanical properties of starch filled LDPE films were examined. Tensile modulus of the composite films increased with increasing starch contents, whereas ultimate tensile strength of the composite films with 9∼23wt% starch was reduced with a little comparing to the starch-free LDPE film. Elongation at break was reduced drastically to ca. 20% of matrix film at 9wt% starch content. Surface of starch was modified by costing with the materials such as ionic, nonionic surfactants, and ethylene oxide/caprolactone block copolymers. The LDPE composite films with 9 and l7wt% surface-modified starch showed 550∼750% and 300∼400% elongation, respectively, thats are remarkable improvements comparing to the pure-starch/LDPS films. This may be related to the modification of starch surface to a low surface energy, resulting in a homogeneous distribution of starch in the matrix polymer, and stability of voids, which could effectively retard the crack propagating toward transverse direction of stress.

[References]

Otey FH, Westhoff RP, Russell CR, Ind. Eng. Chem. Prod. Res. Dev., 16, 305 (1977)
Westhoff RP, Kwolek WF, Otey FH, Starke, 31, 163 (1979)
Lenk RS, Polymer, 21, 371 (1981)
Lenk RS, Merrall EA, Polymer, 22, 1279 (1981)
Griffin GJL, U.S. Patent, 4,016,117 (1977)
Griffin GJL, U.S. Patent, 4,021,388 (1977)
Roper H, Koch H, Starke, 42, 123 (1990)
Manson JA, Sperling LH, "Polymer Blends and Composites," Chap. 12, Plenium Press, New York (1976)
Nielsen LE, Lewis TB, J. Polym. Sci. A: Polym. Chem., 7, 1705 (1969)
Nielsen LE, J. Appl. Polym. Sci., 10, 97 (1966)
Israelachvili JN, "Intermolecular & Surface Forces," 2nd ed., Chap. 15, Academic Press, New York (1991)
Adamson AW, "Physical Chemistry of Surface," 5th ed., Chap. 10, John Wiley & Sons, Inc., New York (1990)

[Referenced By]

[1] Otey FH, Westhoff RP, Russell CR, Ind. Eng. Chem. Prod. Res. Dev., 16, 305 (1977)

[2] Westhoff RP, Kwolek WF, Otey FH, Starke, 31, 163 (1979)

[3] Lenk RS, Polymer, 21, 371 (1981)

[4] Lenk RS, Merrall EA, Polymer, 22, 1279 (1981)

[5] Griffin GJL, U.S. Patent, 4,016,117 (1977)

[6] Griffin GJL, U.S. Patent, 4,021,388 (1977)

[7] Roper H, Koch H, Starke, 42, 123 (1990)

[8] Manson JA, Sperling LH, "Polymer Blends and Composites," Chap. 12, Plenium Press, New York (1976)

[9] Nielsen LE, Lewis TB, J. Polym. Sci. A: Polym. Chem., 7, 1705 (1969)

[10] Nielsen LE, J. Appl. Polym. Sci., 10, 97 (1966)

[11] Israelachvili JN, "Intermolecular & Surface Forces," 2nd ed., Chap. 15, Academic Press, New York (1991)

[12] Adamson AW, "Physical Chemistry of Surface," 5th ed., Chap. 10, John Wiley & Sons, Inc., New York (1990)