Abstract
Polymorphism of syndiotactic polystyrene (sPS) induced by supercritical CO2 (scCO2) was investigated as functions of temperature and pressure by using infrared spectroscopy and X-ray diffraction. When a glassy sPS was incubated in scCO2 at 18 MPa, a modification with the trans-trans-gauche-gauche (t2g2) conformation appeared between 40 °C and 80 °C, and the planar zigzag form appeared above 60 °C. Both forms coexisted between 60 °C and 80 °C. Below the critical temperature of CO2 (31.1 °C) no crystallization occurred at any pressure. When the pressure of CO2 is below the critical pressure (7.2 MPa), the t2g2 form did not appear at any temperature but the planar zigzag form appeared above 90 °C. These results indicate that incubation in supercritical CO2 is necessary for the formation of the t2g2 form. On the other hand, the planar zigzag form was obtained irrespective of the physical states of CO2, but depended on the incubation temperature and pressure. This indicates that the conformational stability of the planar zigzag form depends only on the thermal factors. The crystallization temperature into the planar zigzag form decreased with increasing pressure of CO2 due to the plasticizer effect of CO2.
Similar content being viewed by others
Article PDF
References
N. H. Hartshorne and A. Stuart, “Crystals and the Polarizing Microscope”, Edward Arnold Publishers Ltd., London, 1970.
R. A. Chivers, S. J. Martinez, P. J. Barham, and A. Keller, J. Polym. Sci., Polym. Phys. Ed., 20, 1717 (1982).
L. C. Sawyer and D. T. Grubb, “Polymer Microscopy”, Chapman and Hall Ltd., New York, N.Y., 1987.
M. J. Hill and P. J. Barham, Polymer, 33, 4099 (1992).
L. Reimer, ‘Electron Spectroscopic Imaging’ in “Energy-Filtering Transmission Electron Microscopy” L. Reimer, Ed., Springer-Verlag, GmbH & Co., Berlin, 1984, p 347.
H. Tadokoro, “Structure of Crystalline Polymers”, John Wiley & Sons, Inc., New York, N.Y., 1979.
J. A. Chandler, “X-ray Microanalysis in the Electron Microscope”, North-Holland Publishers, Amsterdam, 1977.
H. D. Keith, F. J. Padden, and R. G. Vadimsky, Science, 150, 1026 (1965).
H. D. Keith, F. J. Padden, and R. G. Vadimsky, J. Polym. Sci., A-2, 4, 267 (1966).
A. Zwijnenburg and A. J. Pennings, Colloid Polym. Sci., 253, 452 (1975).
A. J. Pennings, R. Lagaveen, and R. S. Devries, Colloid Polym. Sci., 255, 532 (1977).
P. J. Barham, Polymer, 23, 1112 (1982).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Nakaoki, T., Fukuda, Y., Nakajima, E. et al. Crystallization Condition of Glassy Syndiotactic Polystyrene in Supercritical CO2. Polym J 35, 430–435 (2003). https://doi.org/10.1295/polymj.35.430
Issue Date:
DOI: https://doi.org/10.1295/polymj.35.430