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Ring‐banded spherulites in poly(ϵ‐caprolactone) blended with hydroxyethyl cellulose acetate as an indication for partial miscibility
Author(s) -
Xiao Q.,
Yan S.,
Rogausch K. D.,
Petermann J.,
Huang Y.
Publication year - 2001
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/app.1263
Subject(s) - materials science , crystallization , hydroxyethyl cellulose , spherulite (polymer physics) , polymer chemistry , miscibility , lamellar structure , morphology (biology) , chemical engineering , polymer , caprolactone , crystallinity , cellulose triacetate , cellulose , composite material , copolymer , biology , engineering , genetics
The morphologies of poly(ϵ‐caprolactone) (PCL) blends with hydroxyethyl cellulose acetate (HECA), a thermotropic liquid crystalline polymer (TLCP), were investigated by optical microscopy. It is demonstrated that when the pure PCL is crystallized from the melt, a spherulitic morphology arises with distinct Maltese crosses. With the addition of the HECA, the spherulites of the PCL/HECA blends show not only the Maltese crosses but also distinct extinction rings (i.e., a ring‐banded spherulitic morphology). The average periodic distance of the extinction rings decreases drastically with the increase of the HECA content from 0.5 to 5 wt % in the mixture, whereas it decreases only slightly with the further increase of HECA. The periodicity of extinction rings is also influenced by the crystallization temperature. The formation of the ring‐banded spherulites of PCL in PCL/HECA blends is explained in terms of stress‐induced twisted lamellar crystallization and used as an indication of the molecular solubility of the HECA in the PCL. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1681–1686, 2001