Chinese Journal of Applied Chemistry ›› 2020, Vol. 37 ›› Issue (6): 642-649.DOI: 10.11944/j.issn.1000-0518.2020.06.190359

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Crystallization and Melting Behaviors of Poly(1,4-cyclohexylene Dimethylene Terephthalate) Studied by Fast-Scan Calorimetry

MIAO Zhongshuoab,MEN Yongfenga*()   

  1. aState Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences,Changchun 130022,China
    bUniversity of Chinese Academy of Sciences,Beijing 100049,China
  • Published:2020-06-01 Online:2020-06-08
  • Contact: MEN Yongfeng
  • Supported by:
    Supported by the National Science Fund for Distinguished Young Scholars(No.51525305)

Abstract:

The crystallization and melting behavior of poly(1,4-cyclohexylene dimethylene terephthalate) (PCT) was studied by fast scanning calorimetry (FSC) combined with traditional differential scanning calorimetry (DSC) in the range of near glass transition temperature and melting temperature (100~270 ℃). The crystallization rate of PCT is faster when the supercooling degree is larger. FSC can effectively inhibit the crystallization of PCT during the cooling process while the traditional DSC can avoid the influence of sample degradation on the experimental results under the lower supercooling degrees. The combination of FSC and DSC can well measure the crystallization kinetics of PCT. The experimental results show that the crystallization rate is the fastest at 175 ℃. FSC is also used to measure the melting point dependence of heating rate after isothermal crystallization, and calibrated on the basis of the modeling of melting kinetics for the determination of the melting point at zero heating rate Tm. The Hoffman-Weeks plot of Tm against Tc with the intersection of Tc=Tm suggested the equilibrium melting point $T_m^o$?315 ℃ of chain-extended infinite-size crystals of PCT.

Key words: poly(1,4-cyclohexylene dimethylene terephthalate), isothermal crystallization, fast scanning calorimetry, zero-entropy production melting point, lamella