Abstract
The crystallization kinetics of fractionated polyethylenes under high pressure was studied by the DTA method for samples having molecular weights of 15500 and 150000. In extended-chain crystallization there was a saturation phenomenon on producing extended-chain crystals. The amount of saturation was dependent on the crystallization temperature. The saturation phenomenon seems to be an important factor for considering the mechanism of growth in extended-chain crystals. The Avrami exponent of extended-chain crystals was almost two. In the case of the folded-chain crystallization, the Avrami exponent was about three, irrespective of pressure. The crystallization rate of folded-chain crystals became more rapid as pressure was increased owing to the depression of the value of excess free energy of the fold surface. The crystallization rate of extended-chain crystals is ako considered to increase with pressure by indirect comparison, and seems to have a maximum crystallization rate near the melting temperature. The estimation of lamellar thickness is discussed for folded-chain crystals produced under high pressure.
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P. D. Calvert and D. R. Uhlmann, J. Polym. Sci., Part A-2, 10, 1811 (1972).
H. Kanetsuna, S. Mitsuhashi, M. Iguchi, T. Hatakeyama, M. Kyotani, and Y. Maeda, J. Polym. Sci., Part C, 42, 783 (1973).
M. Yasuniwa, C. Nakafuku, and T. Takemura, Polym. J., 4, 526 (1973).
D. C. Bassett and B. Turner, Phil. Mag., 29, 285 (1974).
D. C. Bassett and B. Turner, Phil. Mag., 29, 925 (1974).
M. Yasuniwa, R. Enoshita, and T. Takemura, Jpn. J. Appl. Phys., 15, 1421 (1976).
M. Kyotani and H. Kanetsuna, J. Polym. Sci., Part A-2, 12, 2331 (1974).
T. Hatakeyama, H. Kanetsuna, H. Kaneda, and T. Hashimoto, J. Macromol. Sci., B 10, 359 (1974).
Y. Maeda and H. Kanetsuna, J. Polym. Sci., Part A-2, 14, 2057 (1976).
P. J. Flory, J. Am. Chem. Soc., 84, 2857 (1962).
H. H. Hoehn, R. C. Ferguson, and R. R. Hebert, Polym. Eng. Sci., 18, 457 (1978).
S. Sawada and T. Nose, Polym. J., 11, 227 (1979).
L. Mandelkern, “Crystallization of Polymers,” McGraw-Hill, New York, N.Y., 1964, Chapter 8.
D. Turnbull and J. C. Fischer, J. Chem. Phys., 17, 71 (1949).
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Sawada, S., Nose, T. Crystallization Kinetics of Fractionated Polyethylenes at High Pressures by a DTA Method. Polym J 11, 477–483 (1979). https://doi.org/10.1295/polymj.11.477
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DOI: https://doi.org/10.1295/polymj.11.477