TY - GEN
T1 - Flow instabilities of highly entangled thermoplastic polymers
AU - Li, Yanfei
AU - McKenna, Gregory B.
N1 - Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2015
Y1 - 2015
N2 - The flow behaviors of thermoplastic polymers in strong flows have a profound impact on the applications of polymer processing, such as extrusion and injection molding. And many phenomena, such as shark skin and spurt flow, are related to the flow instabilities of polymers. Furthermore, the understanding of how polymer structures affect the flow properties plays a key role in designing the structure-processing-property relationship. In the present work, we have self-built particle tracking/imaging devices on commercial rheometers. By directly visualizing the shear flow fields of polybutadiene (PBD) and polystyrene (PS) solutions, we investigated edge fracture and shear banding, both of which are flow instabilities that could affect the finishing of thermoplastic products. By either optimizing the surface topology or chemically modifying the surface chemistry of the rheometer plates, we were able to prevent interfacial wall slip. Under highly nonlinear viscoelastic flows (Weissenberg number > 200), our results show that there is no compelling evidence of the existence of shear banding. This is opposed to recent literature results which suggest shear banding in comparable conditions.
AB - The flow behaviors of thermoplastic polymers in strong flows have a profound impact on the applications of polymer processing, such as extrusion and injection molding. And many phenomena, such as shark skin and spurt flow, are related to the flow instabilities of polymers. Furthermore, the understanding of how polymer structures affect the flow properties plays a key role in designing the structure-processing-property relationship. In the present work, we have self-built particle tracking/imaging devices on commercial rheometers. By directly visualizing the shear flow fields of polybutadiene (PBD) and polystyrene (PS) solutions, we investigated edge fracture and shear banding, both of which are flow instabilities that could affect the finishing of thermoplastic products. By either optimizing the surface topology or chemically modifying the surface chemistry of the rheometer plates, we were able to prevent interfacial wall slip. Under highly nonlinear viscoelastic flows (Weissenberg number > 200), our results show that there is no compelling evidence of the existence of shear banding. This is opposed to recent literature results which suggest shear banding in comparable conditions.
UR - http://www.scopus.com/inward/record.url?scp=85010664429&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:85010664429
T3 - Annual Technical Conference - ANTEC, Conference Proceedings
BT - ANTEC 2015 - Proceedings of the Annual Technical Conference and Exhibition of the Society of Plastics Engineers
PB - Society of Plastics Engineers
Y2 - 23 March 2015 through 25 March 2015
ER -