The Elasticity of Polymer Melts and Solutions in Shear and Extension Flows

Субботин, А. А.; Malkin, A. Ya.; Куличихин, В. Г.

doi:10.3390/polym15041051

Cited by 6 publications

(2 citation statements)

References 163 publications

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“…ε. To correlate with experimental results [46,47], we expressed the applied strain rate in terms of a dimensionless Weissenberg number [48][49][50] defined as Wi = . ετ R , where τ R is the Rouse time, given by τ R = τ e Z 2 , where Z = l/l e is the average number of entanglements per chain and τ e the entanglement time.…”

Section: Methodsmentioning

confidence: 99%

Bead–Spring Simulation of Ionomer Melts—Studying the Effects of Chain-Length and Associating Group Fraction on Equilibrium Structure and Extensional Flow Behavior

Mohottalalage,

Saab,

Maiti

2023

Polymers

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Ionomers are associative polymers with diverse applications ranging from selective membranes and high-performance adhesives to abrasion- and chemical-resistant coatings, insulation layers, vacuum packaging, and foamed sheets. Within equilibrium melt, the ionic or associating groups are known to form thermally reversible, associative clusters whose presence can significantly affect the system’s mechanical, viscoelastic, and transport properties. It is, thus, of great interest to understand how to control such clusters’ size distribution, shape, and stability through the designed choice of polymer architecture and the ionic groups’ fraction, arrangement, and interaction strength. In this work, we represent linear associating polymers using a Kremer–Grest type bead–spring model and perform large-scale MD simulations to explore the effect of polymer chain-length (l) and fraction (fs) of randomly placed associating groups on the size distribution and stability of formed clusters. We consider different chain-lengths (below and above entanglement), varying fractions of associating groups (represented by ‘sticky’ beads) between 5 and 20%, and a fixed sticky–sticky nonbond interaction strength of four times that between regular non-associating beads. For all melts containing associating groups the equilibrium structure factor S(q) displays a signature ionomer peak at low wave vector q whose intensity increases with increasing fs and l. The average cluster size Nc increases with fs. However, the effect of chain-length on Nc appears to be pronounced only at higher values of fs. Under extensional flows, the computed stress (and viscosity) is higher at higher fs and l regardless of strain rate. Beyond a critical strain rate, we observe fragmentation of the associative clusters, which has interesting effects on the stress/viscous response.

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Section: Methodsmentioning

confidence: 99%

Bead–Spring Simulation of Ionomer Melts—Studying the Effects of Chain-Length and Associating Group Fraction on Equilibrium Structure and Extensional Flow Behavior

Mohottalalage,

Saab,

Maiti

2023

Polymers

View full text Add to dashboard Cite

show abstract

“…Finally, Subbotin et al [ 11 ] presented a review devoted to understanding the role of elasticity in the main flow modes of polymeric viscoelastic liquids—shearing and extension. The flow through short capillaries is the central topic for discussing the input of elasticity to the effects, which are especially interesting for shear.…”

mentioning

confidence: 99%