Extensional Flow of Polymer Melts

1977 ◽  
Vol 21 (3) ◽  
pp. 429-446 ◽  
Author(s):  
Ramesh N. Shroff ◽  
L. V. Cancio ◽  
Mitsuzo Shida
Keyword(s):  
Polymer Melts ◽  
Extensional Flow

Suspensions of monodisperse spheres in polymer melts: particle size effects in extensional flow

2002 ◽  
Vol 42 (1-2) ◽  
pp. 184-190 ◽  
Author(s):  
Jean-François Le Meins ◽  
Paula Moldenaers ◽  
Jan Mewis
Keyword(s):  
Particle Size ◽  
Size Effects ◽  
Polymer Melts ◽  
Extensional Flow ◽  
Particle Size Effects ◽  
Monodisperse Spheres

scholarly journals Recoverable Extensional Flow of Polymer Melts and Its Relevance for Processing

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1512
Author(s):  
Helmut Münstedt
Keyword(s):  
Polymer Melts ◽  
Extensional Flow ◽  
Elongational Flow ◽  
Fused Deposition Modelling ◽  
Extrudate Swell ◽  
Fused Deposition ◽  
Rigid Particles ◽  
Experimental Parameters ◽  
Slit Die

While the uniaxial elongational viscosity is widely investigated, and its relevance for processing is described in the literature, much less has been published on the recoverable extensional flow of polymer melts. This paper presents a short overview of the dependencies of the recoverable elongation on the molecular structure of a polymer, and on some experimental parameters. Its main focus lies on the discussion of processing operations and applications that are largely affected by the elastic components of elongational flow. The recoverable portions of stretched films are considered, and the exploitation of the shrinkage of films, due to the recovery of frozen recoverable deformations, and its role for applications are addressed. The analysis of measurements of velocity fields in the entry region of a slit die and results on the determination of the recoverable elongation from uniaxial experiments, according to the literature, lead to the conclusion of dominant elastic extensions. Considering these facts, the assumptions for Cogswell’s widely used method of determining elongational viscosities under processing conditions from entrance flow are not realistic. As examples of a direct application of extrudate swell from short dies for processing, pelletizing and fused deposition modelling within additive manufacturing are addressed. The special features of extrudate swell from short dies, and uniaxial recoverable elongation for a polymer filled with rigid particles in comparison to an immiscible polymer blend, are presented and discussed.

A theory for the coexistence of coiled and stretched configurational phases in the extensional flow of entangled polymer melts

2021 ◽  
Vol 154 (20) ◽  
pp. 204907
Author(s):  
Mohammad Hadi Nafar Sefiddashti ◽  
Brian J. Edwards ◽  
Bamin Khomami ◽  
Eric S. G. Shaqfeh
Keyword(s):  
Polymer Melts ◽  
Extensional Flow ◽  
Entangled Polymer ◽  
Entangled Polymer Melts
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