Concentrated polymer solutions—III. Viscosity of polyisobutylene solutions in various solvents

Tager, A.A.; Dreval, V.Ye.; Khasina, F.A.

doi:10.1016/0032-3950(63)90335-6

Cited by 20 publications

(4 citation statements)

References 7 publications

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“…A downward curve is visible up to 50 mg mL –1 , with E a – E a 0 = 4 kJ mol –1 , followed by an upward increase until the maximum tested concentration. A similar behavior was described in poly(isobutylene) and cellulose solutions prepared with different solvents where in the low-concentration region E a values versus concentration are curved downward and the absolute value of E a is solvent dependent. , A study regarding poly(isobutylene) also reported a change in the slope to an upward increase on the concentrated regime, as observed here at higher SF concentration . A solution of 0.1 wt % SF in Ca(NO 3 ) 2 /MeOH was estimated to have E a – E a 0 = 8.45 kJ mol –1 .…”

Section: Results and Discussionsupporting

confidence: 79%

“…65,66 A study regarding poly(isobutylene) also reported a change in the slope to an upward increase on the concentrated regime, as observed here at higher SF concentration. 66 A solution of 0.1 wt % SF in Ca(NO 3 ) 2 /MeOH was estimated to have E a − E a 0 = 8.45 kJ mol −1 . 27 For the same concentration, we obtained E a − E a 0 = 0.8 kJ mol −1 , which might reflect a better dissolution of SF in TBAOH(aq) in comparison to the Ca(NO 3 ) 2 /MeOH system.…”

Section: ■ Introductionsupporting

confidence: 79%

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Silk Fibroin Dissolution in Tetrabutylammonium Hydroxide Aqueous Solution

et al. 2019

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Bombyx mori L. silk fibroin (SF) is widely used in different areas due to its ability to form durable and resilient materials with notable mechanical properties. However, in some of these applications the dissolution of SF is required, and this is not often straightforward due to its inability to be dissolved in the majority of common solvents. This work reports a novel approach to dissolve SF using 40 wt % aqueous tetrabutylammonium hydroxide, TBAOH(aq), at mild temperature. A thorough rheological study combined with small-angle X-ray scattering is presented to correlate the SF state in solution with changes in the rheological parameters. The scattering data suggest that the SF conformation in TBAOH(aq) is close to a random coil, possibly having some compact domains linked with flexible random chains. The radius of gyration (R g ) and the molecular weight (M w ) were estimated to be ca. 17.5 nm and 450 kDa, respectively, which are in good agreement with previous works. Nevertheless, a lower M w value was deduced from rheometry (i.e., 321 kDa) demonstrating a low degree of depolymerization during dissolution in comparison to other harsh processes. The transition from a dilute to a semidilute regime coincides with the estimated critical concentration and is marked by the presence of a shear-thinning behavior in the flow curves, violation of the empirical Cox−Merz rule, and an upward increase in the activation energy. This work paves the way toward the development of advanced high-tech SF-based materials.

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Section: Results and Discussionsupporting

confidence: 79%

Section: ■ Introductionsupporting

confidence: 79%

Silk Fibroin Dissolution in Tetrabutylammonium Hydroxide Aqueous Solution

et al. 2019

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“…The E a values are dependent on the nature of polymer and solvent, and polymer concentration [66,67]. Figure S3 in the Supporting Information shows the Arrhenius fits to the data for pure solvent and polymer solution systems.…”

Section: Zero-shear Viscositymentioning

confidence: 99%

Dilute viscoelastic polymer solutions for dielectric heat transfer applications: A molecular dynamics study

Ravikumar¹,

Karathanassis²,

Smith³

et al. 2023

International Journal of Thermofluids

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“…Fig. 8 presents the dependence of the logarithm of initial Newtonian viscosity versus the logarithm of the molecular weight of PI solutions in isooctane (20). This dependence manifests itself by two crossing lines.…”

mentioning

confidence: 89%

Non-Newtonian viscosity of concentrated polymer solutions

Tager¹,

Dreval²

1970

Rheol Acta

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We can say with assurance that the viscosity coefficient is the most sensitive parameter in relation to any possible changes in liquids and liquid mixtures. For example, this parameter can change at the change of concentration of polymer solutions in 12-15 decimal orders. Consequently, the study of viscosity of polymer solutions is very prolific.As Fox and collaborators (l) have already noted that for a satisfactory comprehension of flow processes it is necessary to know the influence of the numerous polymer characteristics such as molecular weight change, temperature, type of solvent and concentration upon viscosity.Prior to 1956 these data were meager and fragmentary. But from this date on the number of works dealing with concentrated polymer solutions has sharply increased. The Chair of Macromolecular Chemistry of the Ural State University devoted much of its attention to this problem. This communication is an attempt to summarize all the experimental data at our disposal.The works of a number of investigators show that the viscosity of low molecular liquids and their mixtures is determined by their structures (2). The same viscositystructure relation should be expected for polymer solutions.According to common notions the structure of any dispers system and polymer system, too, is in close connection with the initial Newtonian viscosity, which is the viscosity of a system with not desintegrated structure (3). Therefore, our early works were devoted to the investigation of the initial Newtonian viscosity of polyisobutylene (PI) and polystyrene (PS) solutions in a wide range of concentrations (4).The point of our interest was the influence of the solvent nature on the solution viscosity. It has a great importance because depending on the quality of solvent either interstructure swelling spontaneously followed by *) Paper presented at the Conference on Advances in Rheology, Glasgow, September 16-18, 1969. dissolution of polymer or intrastructure limited swelling are observed. Consequently, the structure of polymer may be desintegrated step by step by means of changing the quality of solvent and this affects the value of solution viscosity.Therefore, for each polymer the solvents were chosen with different thermodynamic affinity to this polymer (different goodness). The affinity was evaluated quantitatively by conventional methods (5).The results of measurements of the concentration dependence of the Newtonian viscosity are presented in fig. 1. It can be seen that the nature of the solvent affects the value of the initial Newtonian viscosity of concentrated polymer solutions in a different way, depending upon the flexibility of the polymer chain. For instance, the viscosity of a solution of non-polar flexible polymer (PI) depends little upon the nature of solvent. The maximal variation is of a decimal order.The viscosities of equiconcentrated PS solutions in different solvents differ on 2-3 decimal orders. The viscosities of acetylcellulose (AC) solutions in different solvents differ on 4 decimal orders. The maxi...

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Concentrated polymer solutions—III. Viscosity of polyisobutylene solutions in various solvents

Cited by 20 publications

References 7 publications

Silk Fibroin Dissolution in Tetrabutylammonium Hydroxide Aqueous Solution

Silk Fibroin Dissolution in Tetrabutylammonium Hydroxide Aqueous Solution

Dilute viscoelastic polymer solutions for dielectric heat transfer applications: A molecular dynamics study

Non-Newtonian viscosity of concentrated polymer solutions

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