Effect of crystallization temperature on crystal modifications and crystallization kinetics of poly(L-lactide)

Authors

  • Pengju Pan,

    1. Department of Biomolecular Engineering, Tokyo Institute of Technology, 4259-B-55 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
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  • Bo Zhu,

    1. Department of Biomolecular Engineering, Tokyo Institute of Technology, 4259-B-55 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
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  • Weihua Kai,

    1. Department of Biomolecular Engineering, Tokyo Institute of Technology, 4259-B-55 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
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  • Tungalag Dong,

    1. Department of Biomolecular Engineering, Tokyo Institute of Technology, 4259-B-55 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
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  • Yoshio Inoue

    Corresponding author
    1. Department of Biomolecular Engineering, Tokyo Institute of Technology, 4259-B-55 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
    • Department of Biomolecular Engineering, Tokyo Institute of Technology, 4259-B-55 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
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Abstract

The crystalline structure of poly(L-lactide) (PLLA) have been found to quite depend on the crystallization temperatures (Tcs), especially in the range of 100−120°C, which is usually used as the crystallization temperature for the industrial process of PLLA. The analysis of wide-angle X-ray diffraction and Fourier transformed infrared spectroscopy revealed that 110°C is a critical temperature for PLLA crystallization. At Tc < 110°C and Tc ≥ 110°C, the α′ and α crystals were mainly produced, respectively. Besides, the structural feature of the α′-form was illustrated, and it was found that the α′-form has the larger unit cell dimension than that of the α-form. Moreover, the crystallization kinetics of the α′ and α crystals are different, resulting in the discontinuousness of the curves of spherulite radius growth rate (G) versus Tc and the half time in the melt-crystallization (t1/2) versus Tc investigated by Polarized optical microscope and Differential scanning calorimetry, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

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