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Isothermal crystallization behavior of poly( L ‐lactic acid)/organo‐montmorillonite nanocomposites
Author(s) -
Li Xiaoxiu,
Yin Jingbo,
Yu Zhenyang,
Yan Shifeng,
Lu Xiaochun,
Wang Yinjie,
Cao Bin,
Chen Xuesi
Publication year - 2009
Publication title -
polymer composites
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.577
H-Index - 82
eISSN - 1548-0569
pISSN - 0272-8397
DOI - 10.1002/pc.20721
Subject(s) - materials science , crystallization , nanocomposite , montmorillonite , organoclay , isothermal process , chemical engineering , intercalation (chemistry) , avrami equation , melting point , composite material , polymer chemistry , organic chemistry , thermodynamics , chemistry , enthalpy of fusion , physics , engineering
The isothermal crystallization behavior of poly( L ‐lactic acid)/organo‐montmorillonite nanocomposites (PLLA/OMMT) with different content of OMMT, using a kind of twice‐functionalized organoclay (TFC), prepared by melt intercalation process has been investigated by optical depolarizer. In isothermal crystallization from melt, the induction periods ( t i ) and half times for overall PLLA crystallization (100°C ≤ T c ≤ 120°C) were affected by the temperature and the content of TFC in nanocomposites. The kinetic of isothermal crystallization of PLLA/TFC nanocomposites was studied by Avrami theory. Also, polarized optical photomicrographs supplied a direct way to know the role of TFC in PLLA isothermal crystallization process. Wide angle X‐ray diffraction (WAXD) patterns showed the nanostructure of PLLA/TFC material, and the PLLA crystalline integrality was changed as the presence of TFC. Adding TFC led to the decrease of equilibrium melting point of nanocomposites, indicating that the layered structure of clay restricted the full formation of crystalline structure of polymer. The specific interaction between PLLA and TFC was characterized by the Flory‐Huggins interaction parameter ( B ), which was determined by the equilibrium melting point depression of nanocomposites. The final values of B showed that PLLA was more compatible with TFC than normal OMMT. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers