Abstract
An ethylene-propylene random copolymer (EP) in carbon disulfide, toluene, and cyclopentane was found to convert to a thermoreversible gel at the temperature lower than ca. 10°C. Sol⇄gel transition temperatures were measured as a function of polymer concentration using several samples with different propylene contents (PC) and molecular weights. PC varies from 22 to 49 wt%. The sol→gel and gel→sol transition temperatures, where thermal hysteresis was present for each sample, lowered considerably with increasing PC, regardless of differences in molecular weights. The gel-melting behavior was investigated with the aid of the Takahashi theory which is based upon a conjecture that junction points of a gel are fringed micelle crystallites. The theory was well applicable to the present systems. A common linear relation was found to hold between 1/Tmg and lnV2N when the samples had similar PC, where Tmg is the observed gel-melting temperature, V2 is the volume fraction (concentration) of the polymer in the gel, and N is the weight-average degree of polymerization. Further, results of X-ray diffraction, differential scanning calorimetry, and microscopic observation showed that gelation took place through crystallization and that junction points of an EP gel were made up of microcrystallites such as fringed micelles, particularly for a sample with high content of propylene.
Similar content being viewed by others
Article PDF
References
P. J. Flory, “Principles of Polymer Chemistry,” Cornell University Press, Ithaca, N.Y., 1953, Chapter IX.
P. G. de Gennes, “Scaling Concepts in Polymer Physics,” Part A, Cornell University Press, Ithaca, N.Y., 1979, Chapter V.
A. Takahashi, T. Nakamura, and I. Kagawa, Polym. J., 3, 207 (1972).
A. Takahashi and T. Kato, Res. Rep. Fac. Eng. Mie Univ., 1, 97 (1976).
A. Takahashi, M. Sakai, and T. Kato, Polym. J., 12, 335 (1980).
L. Z. Rogovina and G. L. Slonimskii, Russ. Chem. Rev., 43, 503 (1974).
For example, K. Ogasawara, T. Nakajima, K. Yamaura, and S. Matsuzawa, Colloid Polym. Sci., 254, 982 (1976).
Y. C. Yang and P. H. Geil, J. Macromol. Sci. Phys., B22, 463 (1983).
H.-M. Tan, A. Moet, A. Hiltner, and E. Baer, Macromolecules, 16, 28 (1983).
S. Wellinghoff, J. Shaw, and E. Baer, Macromolecules, 12, 932 (1979).
J. Francois, J. Y. S. Gan, and J.-M. Guenet, Macromolecules, 19, 2755 (1986).
H. Matsuda, R. Kashiwagi, and M. Okabe, Polym. J., 20, 189 (1988).
M. Okabe, K. Mitsui, F. Sasai, and H. Matsuda, Polym. J., 21, 313 (1989).
M. Okabe, K. Mitsui, and H. Matsuda, Kobunshi Ronbunshu, 46, 681 (1989).
H. Matsuda, T. Inoue, M. Okabe, and T. Ukaji, Polym. J., 19, 323 (1987).
M. Okabe and H. Matsuda, Polym. Prepr., Jpn., 39, 734 (1990).
J. E. Eldridge and J. D. Ferry, J. Phys. Chem., 58, 992 (1954).
H.-M. Tan, B. H. Chang, E. Baer, and A. Hiltner, Eur. Polym. J., 19, 1021 (1983).
K. Shibatani, Polym. J., 1, 348 (1970).
K. Hyakutake, T. Matsuo, and S. Hashiya, Polym. Prepr., Jpn., 39, 729 (1990).
J. F. Rabek, “Experimental Methods in Polymer Chemistry,” Wiley-Interscience, New York, N.Y., 1980, Chapter 26.
P. J. Flory, J. Chem. Phys., 17, 223 (1949).
L. Mandelkern, J. Appl. Phys., 26, 443 (1955).
For example, R. C. Domszy, R. Alamo, C. O. Edwards, and L. Mandelkern, Macromolecules, 19, 310 (1986).
E. A. Cole and D. R. Holmes, J. Polym. Sci., 46, 245 (1960).
P. R. Swan, J. Polym. Sci., 56, 409 (1962).
M. J. Richardson, P. J. Flory, and J. B. Jackson, Polymer, 4, 221 (1963).
P. J. Holdsworth and A. Keller, J. Polym. Sci., Part B, 5, 605 (1967).
P. J. Holdsworth and A. Keller, Makromol. Chem., 125, 70 (1969).
G. V. Strate and Z. W. Wilchinsky, J. Polym. Sci., Part A-2, 9, 127 (1971).
B. Wunderlich and C. M. Cormier, J. Polym. Sci., Part A-2, 5, 987 (1967).
M. Okabe, M. Isayama, and H. Matsuda, Polym. J., 17, 369 (1985).
F. P. Baldwin and G. V. Strate, Rubber Chem. Technol., 45, 709 (1972).
G. V. Strate, “Ethylene-Propylene Elastomers,” in “Encyclopedia of Polymer Science and Engineering,” Vol. 6, 2nd Ed, H. F. Mark, N. M. Bikales, C. G. Overberger, G. Menges, and J. I. Kroschwitz, Ed., Wiley-Interscience, New York, N.Y., 1986, p 522.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Okabe, M., Mitsui, K., Uranaka, H. et al. Study of Polyolefin Gel in Organic Solvents VII. Thermoreversible Gelation of Ethylene-Propylene Random Copolymer in Carbon Disulfide, Toluene, and Cyclopentane. Polym J 24, 653–667 (1992). https://doi.org/10.1295/polymj.24.653
Issue Date:
DOI: https://doi.org/10.1295/polymj.24.653