금속입자 충전 복합재료의 전단응력에 따른 점도 및 전기 전도도 변화

이건웅; 최동욱; 이상수; 김준경; 박민; Geon-Woong Lee; Donguk Choi; Sang-Soo Lee; Junkyung Kim; Min Park

Polymer(Korea), Vol.26, No.5, 644-652, September, 2002

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금속입자 충전 복합재료의 전단응력에 따른 점도 및 전기 전도도 변화

Effect of Shear Stress on the Viscosity and Electrical Conductivity for the Metal-Filled Composite Materials

이건웅 , 최동욱, 이상수 , 김준경 , 박민 ^†

한국과학기술연구원 고분자하이브리드연구센터, 서울 136-791

Geon-Woong Lee , Donguk Choi, Sang-Soo Lee , Junkyung Kim , and Min Park^†

Polymer Hybrid Research Center, Korea Institute of Science and Technology, Seoul 136-791, Korea

E-mail:

초록

전자파 차폐용 개스킷으로 적용할 수 있는 금속계 입자와 상온경화형 실리콘 수지의 페이스트계에 대한 정량적인 해석을 수행하였다. 금속입자 충전 복합재료의 전기 전도성 및 유변학적 거동은 입자의 형상, 크기, 분산상태에 많은 영향을 받는다. 고충전계에서 입자들은 매우 복잡한 응집상태를 형성하며 전단속도와 같은 외부요인에 의해 응집구조가 변하고 이에 따라 전기 전도도가 달라지게 된다. 본 연구에서는 금속입자의 평균직경 및 분산성에 따른 영향을 점도측정 및 전기 전도도 측정 방법을 통해 해석하였으며 이를 통해 금속입자의 선정기준을 제시하였다. 금속입자의 종류에 따라 점도분포, 전단응력의 영향, 전기 전도성의 변화 등이 차이를 보였다. 상대적으로 직경이 큰 입자에서 전단응력에 의한 영향이 두드러지게 나타났으며 동일 함량에서 분산성의 제어를 통해 점도 및 전기 전도도의 개선이 가능함을 보였다.

This study aims at developing the conductive pastes consisting of room temperature vulcanizing(RTV) silicone and metal powder as matrix and filler, respectively. Electrical and rheological properties of metal-filled polymer composites are in general strongly affected by particle shape, size and dispersion state of the filler. In highly filled systems, particles tend to form very complex agglomerated struture which is easily changed when subjected to shear deformation. And the breakdown of agglomerated particle due to shear usually leads to the change of eletrical conductivity of the composite. In this study, the effect of particle size and dispersion state of filler on the electrical conductivity of the composites are investigated to offer the selection criteria of conductive filler by measuring the rheological properties of uncured composites and the electrical conductivity of the cured composites. It was found that the type of metal filler systematically affected the rheological property, the susceptibility to shear and the degree of change of electrical conductivity of the composite. The effect of shear on the properties is more conspicuous in the composites containing large particle, indicating that both rheological and electrical properties can be improved by controlling the dispersion state at a given filler content.

Keywords:electrical conductivity;metal-filled polymer;RTV silicone;shear viscosity;dispersion state

[References]

Macosko CW, "Rheology: Principles, Measurements and Applications," VCH Pub., Inc., NY (1994)
Batcheler GK, J. Fluid Mech., 83, 97 (1977)
Mewis J, Spaull AJB, Adv. Colloid Interface Sci., 6, 173 (1976)
Metzner AB, J. Rheol., 29, 739 (1985)
Rothon RN, "Mineral Fillers in Thermoplastics: Filler Manufacture and Characterization," Advanced in Polymer Science, vol. 139, Springer-Verlag, Berlin (1999)
Margolis JM, "Conductive Polymers and Plastics," Chapman and Hall, NY (1989)
Bhattacharya SK, "Metal-Filled Polymers: Properties and Applications," Dekker, NY (1986)
Roldughin VI, Vysotskii VV, Prog. Org. Coat., 39, 81 (2000)
Lundberg B, Sundqvist B, J. Appl. Phys., 60, 1074 (1986)
Ryu HR, Semiconductor Monthly, Nov., 67 (1996)
Mewis J, DeGroot LM, Helsen JA, Colloids Surf., 22, 271 (1987)
Lemke T, Bagusat F, Kohnke K, Husemann K, Mogel HJ, Colloids Surf. A: Physicochem. Eng. Asp., 150, 283 (1999)
Otsubo Y, Chem. Eng. Sci., 56(9), 2939 (2001)

[Related Articles]

[1] Macosko CW, "Rheology: Principles, Measurements and Applications," VCH Pub., Inc., NY (1994)

[2] Batcheler GK, J. Fluid Mech., 83, 97 (1977)

[3] Mewis J, Spaull AJB, Adv. Colloid Interface Sci., 6, 173 (1976)

[4] Metzner AB, J. Rheol., 29, 739 (1985)

[5] Rothon RN, "Mineral Fillers in Thermoplastics: Filler Manufacture and Characterization," Advanced in Polymer Science, vol. 139, Springer-Verlag, Berlin (1999)

[6] Margolis JM, "Conductive Polymers and Plastics," Chapman and Hall, NY (1989)

[7] Bhattacharya SK, "Metal-Filled Polymers: Properties and Applications," Dekker, NY (1986)

[8] Roldughin VI, Vysotskii VV, Prog. Org. Coat., 39, 81 (2000)

[9] Lundberg B, Sundqvist B, J. Appl. Phys., 60, 1074 (1986)

[10] Ryu HR, Semiconductor Monthly, Nov., 67 (1996)

[11] Mewis J, DeGroot LM, Helsen JA, Colloids Surf., 22, 271 (1987)

[12] Lemke T, Bagusat F, Kohnke K, Husemann K, Mogel HJ, Colloids Surf. A: Physicochem. Eng. Asp., 150, 283 (1999)

[13] Otsubo Y, Chem. Eng. Sci., 56(9), 2939 (2001)