Paper Number
SM25 

Session
Polymers Solutions, Melts, and Blends

Title
Shear-induced nematic phase in entangled rod-like PEEK melts

Presentation Date and Time
October 12, 2021 (Tuesday) 4:10

Track / Room
Track 1 / Ballroom 5

Authors (Click on name to view author profile)

  1. Parisi, Daniele (FORTH, IESL)
  2. Seo, Jiho (Penn State University, Materials Science and Engineering)
  3. Schaake, Richard P. (SKF, Research and Technology Development)
  4. Rhoades, Alicyn M. (Penn State University, Erie-Behrend)
  5. Colby, Ralph H. (The Pennsylvania State University, Material Science and Engineering)

Author and Affiliation Lines (in printed abstract book)
Daniele Parisi1, Jiho Seo1, Richard P. Schaake2, Alicyn M. Rhoades3 and Ralph H. Colby1
1Material Science and Engineering, The Pennsylvania State University, University Park, PA 16802; 2Research and Technology Development, SKF, Utrecht, The Netherlands; 3Erie-Behrend, Penn State University, Erie, PA 16563

Speaker / Presenter 
Colby, Ralph H.

Keywords
experimental methods; applied rheology; polymer melts; rheology methods

Text of Abstract
We present novel rheo-optical evidence for a shear-induced isotropic-nematic transition exhibited by poly(ether ether ketone) (PEEK) melts of various chain lengths. The key factor is the significant rigidity of the PEEK chain that makes it a rod-like polymer. At low shear rates PEEK is an isotropic rodlike polymer with viscosity scaling as the sixth power of Mw, as predicted by Doi and Edwards. At high shear rates PEEK is fully nematic and at intermediate shear rates there is a biphase. The shear rate at which the longest chains start to form the nematic coincides with the critical shear rate that needs to be exceeded for shear flow to accelerate crystallization kinetics. Consequences of this nematic alignment on crystallization and mechanical properties will be discussed.