Lamellar assembly corresponding to transitions of positively to negatively birefringent spherulites in poly(ethylene adipate) with phenoxy

Graecia Lugito, Eamor Woo

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)

Abstract

Surface morphology of positively or negatively birefringent spherulites in melt-crystallized neat poly(ethylene adipate) (PEA) vs. PEA blend with phenoxy was examined using atomic force microscopy (AFM), scanning electron microscopy, polarizing optical microscopy, thermal analysis, and wide-angle X-ray techniques. Their top-surface morphology in thin film forms was analyzed to fully expounded the lamellar assembly responsible for the opposite birefringence. Top-surface lamellar assemblies in positive/negative types of ringless spherulites (T c = 0, 15, 20, 40 C) and also alternating birefringence of double-ring-banded spherulite (T c = 28 C) of PEA/phenoxy blend were examined with AFM. From the results, spherulite's positive and negative birefringence differs only in interior lamellar arrangements but not lattice geometries. Negative spherulites are composed of radially oriented edge-on lamellae, while positive spherulites are composed of bending/coiling edge-on lamellae. By contrast, the ring-banded spherulites can exhibit both negative and positive birefringence depending on the alternating radial and tangential lamellar arrangement. The addition of phenoxy into PEA could disrupt the regular lamellar bending and promote the singularity of edge-on lamellae; owing to that, the amorphous phenoxy induces looser arrangement of edge-on lamellae with phenoxy being in interlamellar/ interfibrillar regions. The bulky linking pendent group phenoxy, with H-bonding capacity interacting with PEA, also disrupts the regularity of tangential-radial PEA lamellae to display a more zigzag pattern.

Original languageEnglish
Pages (from-to)817-826
Number of pages10
JournalColloid and Polymer Science
Volume291
Issue number4
DOIs
Publication statusPublished - 2013 Apr 1

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Polymers and Plastics
  • Colloid and Surface Chemistry
  • Materials Chemistry

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