Dynamic measurements on polymer solutions and melts

Otter, J. L. den

doi:10.1007/bf01973965

Cited by 30 publications

(3 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Another useful relation can be derived from the agreement between the According to the maximum values of the loss modulus G",,, and <itc. theory of Marvin and Oser33s34 this relation has the form: Gumax = 0.207G'e(7) but the experimental results given inFigure 1, indicate that:Gum., = 0.4Gt, whence ill, = O.C;pRT/C",,,,,…”

mentioning

confidence: 92%

Viscoelastic properties and flow of narrow distribution polybutadienes and polyisoprenes

Vinogradov

Malkin

Yanovskii

et al. 1972

J. Polym. Sci. A‐2 Polym. Phys.

195

View full text Add to dashboard Cite

The dynamic shear modulus and the flow rate through capillaries under constant pressure and under constant velocity of the piston, have been measured for polybutadienes and polyisoprenes of narrow molecular weight distribution with molecular weights ranging, respectively, from 3.8 × 104 to 5.8 × 105 and from 1.06 × 105 to 6.02 × 105. The phenomena of the discontinuous increase of volume flow rate and self‐oscillatory flow regime at critical rates of deformation have been considered in detail. It is proposed that these phenomena are due to the induced transition of the polymer from the fluid to the high‐elastic state at higher deformation rates. As a result, an inference has been made that polybutadienes and polyisoprenes with a narrow molecular weight distribution in the high‐elastic state, behave in certain respects as crosslinked polymers incapable of displaying fluidity. The quantitative relationships among the viscoelastic characteristics measured under dynamic regimes, the parameters determining the critical flow regimes, and the molecular weights of polybutadienes and polyisoprenes have been worked out.

show abstract

mentioning

confidence: 92%

Viscoelastic properties and flow of narrow distribution polybutadienes and polyisoprenes

Vinogradov

Malkin

Yanovskii

et al. 1972

J. Polym. Sci. A‐2 Polym. Phys.

195

View full text Add to dashboard Cite

show abstract

“…Therefore, it was interesting to compare the behavior of the mixture and the copolymer with the same composition in largeamplitude cyclical deformation. The results of these investigations, given in Figure 8, show that for the block copolymer (curves 12) and a mixture (curves 11) of the corresponding composition it is possible to achieve critical regimes of cyclical deformation in the same way as was described for homopolymers. The critical parameters characterizing the regimes of cyclical deformation of the mixture do not differ from the critical parameters of narrow-distribution PI, which is due to its high content in the mixture (70%) and to its compatibility with PB.17 The critical regimes of cyclical deformation of two-component systems, however, must change substantially if the components form block copolymers.…”

Section: Resultsmentioning

confidence: 80%

Critical regimes of oscillatory deformation of polymeric systems above glass transition and melting temperatures

Vinogradov

Isayev

Katsyutsevich

1978

J. Appl. Polym. Sci.

View full text Add to dashboard Cite

SynopsisHigh molecular weight linear polymers and their concentrated solutions were investigated over a wide range of frequencies and amplitudes of oscillatory deformation. At definite critical deformation and stress amplitudes, the resistance to deformation drops abruptly as a result of the rupture of continuity of polymer specimens in the region of action of the highest shear stresses. The lowest critical values of deformation rate amplitudes are inversely proportional to the initial viscosity and correspond quantitatively to the critical shear rates at which the spurt occurs during the flow of polymeric systems in ducts. The spurt effect is due to the transition of the polymer systems to the forced high-elastic state, in which they behave like quasi-cured polymers whose deformability is always limited. Up to the critical values of the stress amplitudes, narrow-distribution high molecular weight linear flexible-chain polymers behave like Hookean bodies, whereas the broad-distribution polymers show a sharply defined nonlinear behavior which asymptotically passes to a spurt. The amplitude dependence of the dynamic characteristics of the high molecular weight linear polymers, as well as their non-Newtonian behavior, is due to polymolecularity. An increase in deformation amplitudes reduces the frequency at which the spurt, and hence the transition of the polymer systems to the high-elastic state, is observed. Therefore, under conditions of oscillatory deformation the physical state (fluid or high-elastic) is determined not only by the frequency but also by the value of deformation. In the high-elastic state region (estimated at low amplitude deformation), the critical deformation amplitude is frequency independent and has an unambiguous relationship with the molecular mass of the chain ( M e ) between the entanglements. For the bulk polymers studied, the spurt in the high-elastic state occurs at stress amplitudes of the order of lo5 N/m2 irrespective of frequency, molecular mass, or polymolecularity. In concentrated polymer solutions, in the highelastic state the critical stress amplitudes decrease with reducing polymer content, whereas the critical deformation amplitudes increase.

show abstract

“…It is an improved version of the apparatus described by Duiser [2] and by den Otter [3,4]. There were several reasons for the construction of an improved automatized version: a) In our laboratory we investigated the ageing process of polymer/plasticizer systems [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

A newly designed coaxial cylinder-type dynamic rheometer

Nijenhuis

Donselaar

1985

Rheol Acta

View full text Add to dashboard Cite

A newly designed dynamic rheometer is described. This apparatus is designed for the purpose of the investigation of the physical ageing process of gels and for the determination of the viscoelastic properties of polymer melts. With this instrument the dynamic moduli can be determined very accurately in a range of about' 8 decades (-2 < log G' < 5.3 and -3 < log G" < 5.4; G' and G" in N/m 2) and in a frequency range of more than 6 decades (5 • 10 -s -100 Hz) with an accuracy and stability of 0.025%. Results are shown of measurements on a silicon oil (with loss angles deviating only little from 90°), on a gel of polyvinyl chloride in Reomol (with loss angles deviating only little from 0 °) and on a polystyrene melt for which, at low frequencies, the dependencies of the storage and loss moduli on the frequency are quadratic and linear, respectively.

show abstract

Dynamic measurements on polymer solutions and melts

Cited by 30 publications

References 10 publications

Viscoelastic properties and flow of narrow distribution polybutadienes and polyisoprenes

Viscoelastic properties and flow of narrow distribution polybutadienes and polyisoprenes

Critical regimes of oscillatory deformation of polymeric systems above glass transition and melting temperatures

A newly designed coaxial cylinder-type dynamic rheometer

Contact Info

Product

Resources

About