Polymorphic and miscibility behavior in crystalline/crystalline blends of poly(pentamethylene terephthalate) with poly(heptamethylene terephthalate)

Kai Cheng Yen, Eamor M. Woo

研究成果: Article同行評審

7 引文 斯高帕斯(Scopus)

摘要

Background: The phase behavior of blends of semicrystalline aryl polyesters with long methylene segments (-(CH2)n-with n = 5 or 7) in the repeat units has not been much studied. Thus, crystalline/crystalline blends comprising monomorphic poly(pentamethylene terephthalate) (PPT) and polymorphic poly(heptamethylene terephthalate) (PHepT) were prepared and the crystal growth kinetics, polymorphism behavior and miscibility in this blend system were probed using polarized-light opticalmicroscopy, differential scanning calorimetry and wide-angle X-ray diffraction. Results: The PPT/PHepT blends of all compositions were first proven to bemiscible in the melt state or quenched amorphous phase, whose interaction strength was determined (χ12 = -0.35), showing favorable interactions and phase homogeneity. Although the spherulites of neat PPT and PHepT could exhibit ring bands at different crystallization temperature (Tc) ranges (100-110 and 50-65 °C, respectively), the spherulites of PPT/PHepT (50/50) blend became ringless in the range 50-110 °C. Growth analysis and polymorphic behavior in the crystalline phases of the blends provided extra evidence for the miscibility between these two crystalline polymers. Spherulitic growth rates of PPT in the PPT/PHepT blends were significantly reduced in comparison with those of neat PPT. In addition, miscible blending of a small fraction of monomorphic PPT (20 wt%) with polymorphic PHepT altered the crystal stability and led to the originally polymorphic PHepT exhibiting only the β-crystal form when melt-crystallized at all values of Tc. Conclusion: The highly intimate mixing in polymer chains of crystalline PPT and PHepT causes significant disruption in ring-band patterns and reduction in crystallization rates of PPT as well as alteration in the polymorphic behavior of PHepT.

原文English
頁(從 - 到)1380-1389
頁數10
期刊Polymer International
58
發行號12
DOIs
出版狀態Published - 2009 12月

All Science Journal Classification (ASJC) codes

  • 聚合物和塑料
  • 有機化學
  • 材料化學

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