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Isothermal crystallization and chain mobility of poly(L‐lactide)
Author(s) -
Iannace S.,
Nicolais L.
Publication year - 1997
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/(sici)1097-4628(19970502)64:5<911::aid-app11>3.0.co;2-w
Subject(s) - crystallization , supercooling , isothermal process , materials science , amorphous solid , glass transition , polymer chemistry , thermodynamics , phase (matter) , lactide , chemical engineering , polymer , crystallography , composite material , chemistry , copolymer , organic chemistry , physics , engineering
Isothermal melt crystallization of poly(L‐lactide) (PLLA) has been studied in the temperature range of 90 to 135°C. A maximum in crystallization kinetic was observed around 105°C. A transition from regime II to regime III is present around 115°C. The crystal morphology is a function of the degree of undercooling. At crystallization temperatures (T c ) below 105°C, further crystallization occurs upon heating; this behavior is not detected for T c above 110°C. The analysis of the heat capacity increment at glass transition temperature (T g ) and of dielectric properties of PLLA indicates the presence of a fraction of the amorphous phase which does not relax at the T g , and the amount of this so‐called rigid amorphous phase is a function of T c . © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 911–919, 1997