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Reorganization of Lamellar Diblock Copolymer Poly(ε‐caprolactone)‐ block ‐poly(4‐vinylpyridine) in the Melting Temperature Range
Author(s) -
Chen Lanlan,
Jiang Jing,
Zhuravlev Evgeny,
Wei Lai,
Schick Christoph,
Xue Gi,
Zhou Dongshan
Publication year - 2015
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201500246
Subject(s) - recrystallization (geology) , lamellar structure , materials science , copolymer , annealing (glass) , differential scanning calorimetry , melting point , kinetics , polymer chemistry , crystallization , atmospheric temperature range , avrami equation , chemical engineering , thermodynamics , crystallography , enthalpy of fusion , composite material , chemistry , polymer , paleontology , physics , quantum mechanics , engineering , biology
The reorganization kinetics of the “original” lamellar diblock copolymer poly(ε‐caprolactone)‐ block ‐poly(4‐vinylpyridine) crystals formed at 260 K is studied in the melting region from 270 K (10 K below the onset of the melting peak of original crystals) to 310 K (the melting peak temperature) on the time scale starting from 10 −4 to 10 2 s by ultrafast differential scanning calorimetry. Different reorganization pathways are observed in this temperature range. Annealing at temperatures below 295 K leads to further stabilization of original crystals by secondary crystallization. At annealing temperatures higher than 295 K, crystals partially melt and the reorganization occurs via the melting–recrystallization. For even higher temperature, such as 310 K, the melting is completed within a few milliseconds and recrystallization starts from the nuclei formation. The sigmoidal recrystallization kinetics is analyzed by the Avrami equation. It is found that the copolymer experiences about one order of magnitude slower recrystallization rate and has higher melting peak temperatures of crystals formed after recrystallization than the homopolymer. The slower recrystallization kinetics in the copolymer is discussed from the viewpoint of the nanoscale spatial constraint and the intermediate state prior to the recrystallization.