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Molecular Entanglement and Electrospinnability of Biopolymers
Published on: September 3, 2014
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Unexpected Stretching of Entangled Ring Macromolecules.
1Department of Chemical and Biochemical Engineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark.
Physical Review Letters
|June 8, 2019
Summary
Entangled ring polymers show unique responses to stretching. Unlike linear polymers, rings dramatically thicken at low stretch rates due to unraveling, but thin at high rates.
Area of Science:
- Polymer physics
- Rheology
- Macromolecular science
Background:
- Entangled nonconcatenated ring macromolecules adopt compact conformations at equilibrium.
- Unlike linear polymers, ring polymers do not form an entanglement network in the melt state.
Purpose of the Study:
- To investigate the rheological response of entangled ring polymers under uniaxial stretching.
- To compare the behavior of ring polymers with linear polymers during stretching.
Main Methods:
- Uniaxial stretching experiments on entangled ring macromolecules.
- Rheological analysis of viscosity changes at varying stretch rates.
Main Results:
- Ring polymers exhibit unique strain-hardening behavior distinct from linear polymers.
- At low stretch rates, ring polymer viscosity dramatically increases (thickens) due to conformational unraveling.
- At high stretch rates, ring polymers show viscosity thinning, similar to entangled linear polymers, with minor differences.
Conclusions:
- Entangled ring polymers possess a unique rheological response to uniaxial stretching.
- The conformational dynamics of ring polymers dictate their distinct melt thickening and thinning behaviors under stress.
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