| 학회 | 한국고분자학회 |
| 학술대회 | 2005년 가을 (10/13 ~ 10/14, 제주 ICC) |
| 권호 | 30권 2호 |
| 발표분야 | 복합재료 |
| 제목 | Mechanical properties of polymer/clay nanocomposites hybridized via master batch approach |
| 초록 | The morphology and tensile properties of polystyrene (PS)/clay and poly (methyl methacrylate) (PMMA)/clay nanocomposites are discussed. The melt compounding of a master batch (clay pre-exfoliated via incorporation of charged polystyrene nanobeads into pristine Na-montmorillonite) was carried out with a twin-screw extruder. Two kinds of the polymer nanobeads synthesized by emulsifier-free emulsion polymerization using a cationic comonomer were used. In one case, to guarantee the incorporated polymer nanobeads from its melting in-between clay platelets and, hence, to prevent restacking of the latter upon melt processing, crosslinked nanobeads were synthesized. The master batch clays exhibited significantly reduced intensities of diffraction peaks in a wide-angle range, suggesting partial exfoliation of the clay layers, whereas for the nanocomposites, remarkable contraction of the gallery was noted. Such severe restacking of the clay layers upon melt processing is ascribed to a thermal instability of a quarternary ammonium group1-5 on the surface of the polymer nanobeads at high temperature and to a consequent moving of the nanobeads away from clay sheet surface under an applied shear. This eventually resulted in the phase separation in the nanocomposites. The mechanical properties revealed slight enhancement in tensile strength and modulus for PS/clay nanocomposites and only modulus for PMMA/clay nanocomposites (그림1). Finally, thermodynamic stability of the clay-nanobead system is discussed6, 7. Annealing the masterbatches at the processing temperature (180 C) for 24 hr did not result in any noticeable changes in clay structure. Thus, the exfoliated clay structure is maintained even under prolonged annealing. This suggests that by adjusting the compounding conditions the processibility of the master batch clay can be improved. Fig. 1. Tensile properties of the PS/clay nanocomposites. 참고문헌 1. X. Fu, S. Qutubuddin, Polymer, 42, 807-813 (2001). 2. M. Kato, A. Usuki, In Polymer-clay nanocomposites; Pinnavaia T. J.; Beall G.W.; Wiley series in polymer science, Chichester (UK), 2000, pp 97-109. 3. R. A. Vaia, E. P. Giannelis, Macromolecules, 30, 8000-8009 (1997). 4. R. A. Vaia, K. D. Jandt, et al., Chem. Mater., 8, 2628-2635 (1996). 5. C. I. Park, O. O. Park; J. G. Lim, H. J. Kim, Polymer, 42, 7465-7475 (2001). 6. D. R. Robello, et al. J. Amer. Chem. Soc., 126, 8118-8119 (2004). 7. C. Singh, A. Balazs, Polym. Int., 49, 469-471 (2000). |
| 저자 | KhvanSvetlana, 이상수, 임순호, 김준경 |
| 소속 | 한국과학기술(연) |
| 키워드 | nanobeads; polymer; clay; nanocomposites; tensile strength; modulus; master batch |
