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Journal of Thermal Analysis and Calorimetry

, Volume 103, Issue 1, pp 339–345 | Cite as

DSC and morphological studies on the crystallization behavior of β-nucleated isotactic polypropylene composites filled with Kevlar fibers

  • Yewen Cao
  • Jiachun Feng
  • Peiyi Wu
Article

Abstract

The crystallization behavior of β-nucleated isotactic polypropylene (PP) composites filled with Kevlar fibers (KFs), as well as that of non-nucleated PP/KF composites for comparison, was investigated using differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The morphological observations revealed that the KF addition could induce thick α-transcrystalline layer around their surfaces in PP/KF composites, while no obvious transcrystalline layer could be detected in β-nucleated PP/KF composites. Detailed DSC investigations suggested that for the PP/KF composites, the dominant modification was α-form, and the crystallization process of matrix was promoted by KF addition, as illustrated by faster isothermal crystallization rate, shorter induction time, and higher crystallization temperature. However, for β-nucleated PP/KF composites, the main modification was β-form, and their crystallization characteristics were independent of KF addition, indicating that the α-nucleating effect of KFs was absent in this system. The DSC results were confirmed by further rheological and wide angle X-ray diffraction (WAXD) studies. The mechanism of the formation of transcrystalline layer was also discussed.

Keywords

DSC POM β-Nucleated isotactic polypropylene Kevlar fiber Transcrystalline layer 

Notes

Acknowledgements

We gratefully acknowledge the financial support from the National Natural Science Foundation of China (Grant No. 20874017, 50673021), the Shanghai-Unilever Research and Development Fund (09520715500), and the National Hi-Tech Research & Development Program (2007AA03Z450).

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Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2010

Authors and Affiliations

  1. 1.Key Laboratory of Molecular Engineering of Polymers of Ministry of Education, Department of Macromolecular Science and Laboratory of Advanced MaterialsFudan UniversityShanghaiPeople’s Republic of China

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