Elongational viscosity of poly(propylene carbonate) melts: tube-based modelling and primitive chain network simulations

Wagner, Manfred H.; Narimissa, Esmaeil; Masubuchi, Yuji

doi:10.1007/s00397-022-01373-w

Cited by 4 publications

(2 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Instead of empirical correlations between friction coefficient and segmental orientation, the ERS model provides an analytical and parameter-free relation of friction reduction as a function of chain stretch. By primitive chain network simulations using the parameter-free universal relation of monomeric friction reduction derived from the ERS model, Wagner et al 11 demonstrated the equivalence with empirical friction reduction models for three poly(propylene carbonate) melts and a polystyrene (PS) melt.…”

Section: Introductionmentioning

confidence: 99%

Rheology of Poly(α-olefin) Bottlebrushes: Effect of Self-Dilution by Alkane Side Chains

Wagner,

Hirschberg

2024

Macromolecules

Self Cite

View full text Add to dashboard Cite

Bottlebrush polymers are combs with extremely high grafting density along their backbone chain. We consider the rheology of bottlebrush poly(α-olefins) with side chains ranging from 6 carbons [poly(1-octene)] to 16 carbons [poly(1octadecene)] as investigated by Loṕez-Barroń et al. (J. Rheol. 2019, 63 (6), 917−926). We argue that the backbone chain of poly(α-olefins) is diluted by the unentangled alkane side chains and that the rheology of poly(α-olefin) bottlebrushes is equivalent to that of poly(1-methylethylene), i.e., atactic polypropylene diluted by a low-molecular-weight solvent. We show that this approach is in agreement with the decreasing plateau modulus of the poly(α-olefins) with increasing side chain length, and it allows to replace empirical correlations by a relation based on physical arguments. The specific strong transient strain hardening in elongational flow shows similar features as observed for entangled solutions of linear polymers and can be explained by the enhanced relaxation of stretch model if self-dilution of the poly(α-olefins) is taken into account. Due to the large difference between the disengagement time d and Rouse time R , the orientation and stretch of backbone chains are well separated, and strain hardening starts after full orientation at Weissenberg numbers above Wi 0.3 R R =. The amount of strain hardening increases with increasing dilution, and at high Wi R , all poly(α-olefins) are expected to reach the same steady-state elongational stress.

show abstract

Section: Introductionmentioning

confidence: 99%

Rheology of Poly(α-olefin) Bottlebrushes: Effect of Self-Dilution by Alkane Side Chains

Wagner,

Hirschberg

2024

Macromolecules

Self Cite

View full text Add to dashboard Cite

show abstract

“…For example, in a follow-up work by Masubuchi et al, 25 the SORF function derived from PS does not work equally well with other samples. Nevertheless, in a more recent work, 26 Masubuchi and his co-workers successfully modeled the extensional rheology of the poly(propylene carbonate) (PPC) melt with the SORF function adjusted for PS. Thus, their function could contain some universal aspects of the polymer melt.…”

Section: Introductionmentioning

confidence: 99%

Potential Universal Extensional Rheology in Concentrated Polymeric Liquids

Jiang

2024

Macromolecules

View full text Add to dashboard Cite

Polymer dynamics are special, in that they are always insensitive to the chemical details of the monomers. However, recent experiments show that the nonlinear extensional rheology of concentrated polymeric liquids has a nonuniversal feature. In this work, the variation of segmental frictional coefficient under flows, which is thought to be the critical factor in explaining the observed nonuniversality, is investigated in the coarse-grained (CG) molecular dynamics (MD) simulations of polymer melts. The frictional coefficients in the simulations are quantified from the expressions we proposed very recently [Jiang, N.; van Ruymbeke, E., Macromolecules 2023, 56 (8), 2911–2929], which are based on the analytical relationships between the frictional coefficients and the observable rheological and structural properties. After the validation of the simulations with experimental data and our expressions, it is shown that those frictional coefficients can be universally related to the projection areas of the polymer coils in the plane normal to the direction of elongation. Moreover, this projection–friction relationship indicates a Kuhn-scale criterion of extensional viscosity, which suggests that a similar extensional rheology will be observed when the materials have the same number of Kuhn segments per chain N k and the same reduced Kuhn density n k defined as the ratio of the Kuhn length to the packing length. This criterion is tested on a series of new simulation systems designed to show similar steady-state extensional viscosities as a function of the reduced extensional rate, as well as the existing experimental data in the literature. The results of this work provide a helpful guideline in searching for the potential universal extensional rheology in the experimental samples.

show abstract

The effect of rotationality on nonlinear shear flow of polymer melts and solutions

Wagner,

Liu,

Huang

2024

Rheol Acta

View full text Add to dashboard Cite

By considering the rotationality of shear flow, we distinguish between tube segments created by reptation before the inception of shear flow and those created during flow. Tube segments created before inception of shear flow experience both stretch and orientation, while tube segments created after inception of flow are not stretched, but are only aligned in the flow direction. Based on this idea, the Rotation Zero Stretch (RZS) model allows for a quantitative description of the start-up of shear flow and stress relaxation after step-shear strain experiments, in agreement with data of polystyrene long/short blends and corresponding polystyrene 3-arm star polymers investigated by Liu et al. (Polymer 2023, 281:126125), as well as the shear viscosity data of poly(propylene carbonate) melts reported by Yang et al. (Nihon Reoroji Gakkaishi 2022, 50:127–135). In the limit of steady-state shear flow, the RZS model converges to the Doi-Edwards IA model, which quantitatively describes the steady-state shear viscosity of linear polymer melts and long/short blends. The assumption of “non-stretching” of tube segments created during rotational flow is therefore in agreement with the available experimental evidence. Three-arm star polymers behave in a similar way as corresponding blends of long and short polymers confirming the solution effect of the short arm in asymmetric stars. The analysis of step-shear strain experiments reveals that stress relaxation is at first dominated by stretch relaxation, followed at times larger than the Rouse stretch relaxation time by relaxation of orientation as described by the damping function of the Doi-Edwards IA model. The RZS model does not require any nonlinear-viscoelastic parameter, but relies solely on the linear-viscoelastic relaxation modulus and the Rouse stretch relaxation time. Graphical Abstract

show abstract

Elongational viscosity of poly(propylene carbonate) melts: tube-based modelling and primitive chain network simulations

Cited by 4 publications

References 52 publications

Rheology of Poly(α-olefin) Bottlebrushes: Effect of Self-Dilution by Alkane Side Chains

Rheology of Poly(α-olefin) Bottlebrushes: Effect of Self-Dilution by Alkane Side Chains

Potential Universal Extensional Rheology in Concentrated Polymeric Liquids

The effect of rotationality on nonlinear shear flow of polymer melts and solutions

Contact Info

Product

Resources

About