Crystal Nucleation in Flowing Polymer Melts

1983 ◽  
pp. 139-153
Author(s):  
Mark S. Pucci ◽  
Stephen H. Carr
Keyword(s):  
Polymer Melts ◽  
Crystal Nucleation

scholarly journals Monodisperse Polymer Melts Crystallize via Structurally Polydisperse Nanoscale Clusters: Insights from Polyethylene

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 447 ◽  
Author(s):  
Kyle Wm. Hall ◽  
Timothy W. Sirk ◽  
Simona Percec ◽  
Michael L. Klein ◽  
Wataru Shinoda
Keyword(s):  
Large Scale ◽  
Polymer Melts ◽  
Polymeric Materials ◽  
Crystalline Polymer ◽  
Crystal Nucleation ◽  
Stem Length ◽  
Polymer Crystal ◽  
Polyethylene Melts ◽  
Nanoscale Clusters ◽  
Entangled Polymer Melts

This study demonstrates that monodisperse entangled polymer melts crystallize via the formation of nanoscale nascent polymer crystals (i.e., nuclei) that exhibit substantial variability in terms of their constituent crystalline polymer chain segments (stems). More specifically, large-scale coarse-grain molecular simulations are used to quantify the evolution of stem length distributions and their properties during the formation of polymer nuclei in supercooled prototypical polyethylene melts. Stems can adopt a range of lengths within an individual nucleus (e.g., ∼1–10 nm) while two nuclei of comparable size can have markedly different stem distributions. As such, the attainment of chemically monodisperse polymer specimens is not sufficient to achieve physical uniformity and consistency. Furthermore, stem length distributions and their evolution indicate that polymer crystal nucleation (i.e., the initial emergence of a nascent crystal) is phenomenologically distinct from crystal growth. These results highlight that the tailoring of polymeric materials requires strategies for controlling polymer crystal nucleation and growth at the nanoscale.

Polymer Nucleation under High-Driving Force, Long-Chain Conditions: Heat Release and the Separation of Timescales

2019 ◽  
Author(s):  
Kyle Hall ◽  
Simona Percec ◽  
Michael Klein
Keyword(s):  
Driving Force ◽  
Polymer Melts ◽  
Early Stage ◽  
Polymer Crystallization ◽  
Crystal Nucleation ◽  
Crystal Formation ◽  
Local Structures ◽  
Entangled Polymer ◽  
Entangled Polymer Melts ◽  
Chain Level

This study reveals important features of polymer crystal formation at high-driving forces in entangled polymer melts based on simulations of polyethylene. First and in contrast to small-molecule crystallization, the heat released during polymer crystallization does not appreciably influence structural details of early-stage, crystalline clusters (crystal nuclei). Second, early-stage polymer crystallization (crystal nucleation) can occur without substantial chain-level relaxation and conformational changes. This study's results indicate that local structures and environments guide crystal nucleation in entangled polymer melts under high-driving force conditions. Given that such conditions are often used to process polyethylene, local structures and the separation of timescales associated with crystallization and chain-level processes are anticipated to be of substantial importance to processing strategies. This study highlights new research directions for understanding polymer crystallization.

Crystal nucleation in sheared polymer melts

1978 ◽  
Vol 18 (3) ◽  
pp. 215-221 ◽  
Author(s):  
P. G. Andersen ◽  
S. H. Carr
Keyword(s):  
Polymer Melts ◽  
Crystal Nucleation

Polymer Nucleation under High-Driving Force, Long-Chain Conditions: Heat Release and the Separation of Timescales

2019 ◽  
Author(s):  
Kyle Hall ◽  
Simona Percec ◽  
Michael Klein
Keyword(s):  
Driving Force ◽  
Polymer Melts ◽  
Early Stage ◽  
Polymer Crystallization ◽  
Crystal Nucleation ◽  
Crystal Formation ◽  
Local Structures ◽  
Entangled Polymer ◽  
Entangled Polymer Melts ◽  
Chain Level

This study reveals important features of polymer crystal formation at high-driving forces in entangled polymer melts based on simulations of polyethylene. First and in contrast to small-molecule crystallization, the heat released during polymer crystallization does not appreciably influence structural details of early-stage, crystalline clusters (crystal nuclei). Second, early-stage polymer crystallization (crystal nucleation) can occur without substantial chain-level relaxation and conformational changes. This study's results indicate that local structures and environments guide crystal nucleation in entangled polymer melts under high-driving force conditions. Given that such conditions are often used to process polyethylene, local structures and the separation of timescales associated with crystallization and chain-level processes are anticipated to be of substantial importance to processing strategies. This study highlights new research directions for understanding polymer crystallization.

The tube diameter in polymer melts, its existence. and its relation to the quantum Hall effect

1994 ◽  
Vol 4 (6) ◽  
pp. 843-862 ◽  
Author(s):  
Arkady L. Kholodenko ◽  
Thomas A. Vilgis
Keyword(s):  
Hall Effect ◽  
Quantum Hall Effect ◽  
Polymer Melts ◽  
Quantum Hall ◽  
Tube Diameter

On Dispersed Crystallization in Polymer Melts as Proceeding from a Quenched Boundary

1988 ◽  
Vol 3 (4) ◽  
pp. 175-183 ◽  
Author(s):  
H. Janeschitz-Kriegl ◽  
G. Krobath
Keyword(s):  
Polymer Melts
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