4.7 Article

Flow-induced crystallization of long chain aliphatic polyamides under a complex flow field: Inverted anisotropic structure and formation mechanism

Journal

POLYMER
Volume 73, Issue -, Pages 91-101

Publisher

ELSEVIER SCI LTD
DOI: 10.1016/j.polymer.2015.07.029

Keywords

Flow-induced crystallization; Complex flow field; Long chain aliphatic polyamides

Funding

  1. R&D Program of the Ministry of Science and Technology [2013BAE02B02]
  2. National Natural Sciences Foundation of China [51173195]
  3. Engineering and Physical Sciences Research Council [EP/L027011/1, EP/K004204/1, EP/G042365/1] Funding Source: researchfish
  4. EPSRC [EP/K004204/1, EP/G042365/1, EP/L027011/1] Funding Source: UKRI

Ask authors/readers for more resources

The present work deals with the flow-induced multiple orientations and crystallization structure of polymer melts under a complex flow field. This complex flow field is characteristic of the consistent coupling of extensional pulse and closely followed shear flow in a narrow channel. Utilizing an ingenious combination of an advanced micro-injection device and long chain aliphatic polyamides (LCPA), the flow-induced crystallization morphology was well preserved for ex-situ synchrotron micro-focused wide angle X-ray scattering (mu WAXS) as well as small angle X-ray scattering (SAXS). An inverted anisotropic crystallization structure was observed in two directions: perpendicular and parallel to the flow direction (FD). The novel anisotropic morphology implies the occurrence of wall slip and global fountain flow under the complex flow field. The mechanism of structure formation is elucidated in detail. The experimental results clearly indicate that the effect of extensional pulse on the polymer melt is restrained and further diminished due to either the transverse tumble of fountain flow or the rapid retraction of stretched high molecular weight tails. However, the residual shish-kebab structures in the core layer of the far-end of channel suggest that the effect of extensional pulse should be considered in the small-scaled geometries or under the high strain rate condition. (C) 2015 Elsevier Ltd. All rights reserved.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.7
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available