Directed Crystallisation of Poly(ε-caprolactone) using a Low-Molar-Mass Self-Assembled Template

✍ Scribed by Supatra Wangsoub; Robert H. Olley; Geoffrey R. Mitchell

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 682 KB
• Volume: 206
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.200500176

✦ Synopsis

Abstract

Summary: We show that small quantities of dibenzylidene sorbitol dispersed in poly(ε‐caprolactone) coupled with shear flow provide a self‐assembling nanoscale framework to yield high levels of crystal orientation. During modest shear flow of the melt, the additive forms highly extended nanofibrils which adopt a preferred alignment with respect to the flow field, and on cooling polymer crystallisation is directed by these fibrils. We use in situ time‐resolving SAXS and WAXS techniques to explore how this behaviour can be modified by the composition, the shear rate and strain as well as the temperature at which the shear flow is imposed. SAXS studies show that the 3% DBS completely dissolves in the PCL melt at temperatures ≥120 °C and that any shear flow imposed at temperatures above such values is ineffective in directing crystallisation.

SAXS pattern of crystallized PCL after cooling.

imageSAXS pattern of crystallized PCL after cooling.