| 학회 |
한국고분자학회 |
| 학술대회 |
2005년 가을 (10/13 ~ 10/14, 제주 ICC) |
| 권호 |
30권 2호 |
| 발표분야 |
복합재료 |
| 제목 |
Morphology control of polypropylene/layered silicate nanocomposites: A potential of Electric Field utilization |
| 초록 |
The incorporation of layered silicates into polymers provides an exciting way of designing materials whose value-added properties can not be shared by conventional composites and adjusted for countless practical applications. Morphology control is a crucial step toward the realization of composite design for property optimization. Recently we have invented a novel method for fabricating polypropylene (PP)/clay nanocomposites by applying the electric field. Electric field was found to induce destruction of the layer-stacking or the orientation of the silicate layers according to the electric field type, AC or DC. The mechanism was made clear via investigating the real-time microstructural evolution of PP/clay nanocomposites under electric field by in-situ synchrotron wide-angle X-ray scattering (WAXS) analysis and transmission electron microscopy (TEM). Dielectric analysis indicates that the destruction of the layer-stacking is ascribed to the detachment of cationic surfactants from the silicate layers caused by the strong electric field. AC field gives rise to the change in the charge distribution of bound ions resulting in surfactant detachment. The charge balance between anionic aluminosilicate layers and cationic surfactants cannot be maintained anymore. As a consequence, the layer-stacking is destroyed. Meanwhile, the orientation of the silicate layers due to DC field can be explained from analogy with the electrorheological phenomenon using the simple polarization model. Transient behavior between AC and DC also has been investigated under AC field with low frequency. Rheology implies that the dielectrophoretic motion and exfoliation of the clay are occurring at the same time in low frequency region. AC field with low frequency induces the oscillating motion of clay within polymer matrix resulting in extraordinary rheological behavior. AC frequency effect on the clay motion is evidenced by non-linear regression. An analysis of output torque data from rheometer confirms the oscillation of G’ resulting from the dielectrophoretic motion of clay under AC field. The in-situ observation of the transient clay motion under AC field with low frequency as well as the investigation on the two different microstructural evolutions under AC and DC fields provide the potential of electric field as a breakthrough to realize the morphology design in polymer/clay nanocompoisites. |
| 저자 |
박준욱1, 최양석1, 조광수2, 안경현1, 이승종1
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| 소속 |
1서울대, 2경북대 |
| 키워드 |
electric field; clay; nanocomposites; wide-anlge X-ray scattering; dielectric analysis; rheology
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| E-Mail |
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