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.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.