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Effect of molecular weight on crystallization behavior of poly (lactic acid) under isotherm and non‐isotherm conditions
Author(s) -
Zirak Nader,
Shirinbayan Mohammadali,
Farzaneh Sedigheh,
Tcharkhtchi Abbas
Publication year - 2022
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.5603
Subject(s) - nucleation , crystallization , materials science , differential scanning calorimetry , isothermal process , optical microscope , amorphous solid , morphology (biology) , chemical engineering , lactic acid , thermodynamics , crystallography , scanning electron microscope , composite material , chemistry , biology , bacteria , engineering , genetics , physics
The effect of molecular weight on the crystallization behavior of poly(lactic acid) (PLA) both isothermally and non‐isothermally was studied using differential scanning calorimetry and polarized optical microscopy. Two distinct crystal forms (α and α′) were investigated under normal conditions of crystallization for different molecular weights. Using microscopy, the growth rate of spherulites was measured and the nucleation rate was estimated. Heterogeneous nucleation and morphology with a variant α and α′ forms have been proposed. Spherulites from low molecular mass PLA contained more interlamellar amorphous phase. In addition, the results showed more rapid crystallization of α′ than the α form in isothermal conditions.