Viscoelastic properties and flow of narrow distribution polybutadienes and polyisoprenes

Vinogradov, G. V.; Malkin, A. Ya.; Yanovskii, Yu. G.; Borisenkova, E. K.; Yarlykov, B. V.; Berezhnaya, G. V.

doi:10.1002/pol.1972.160100609

Cited by 195 publications

(96 citation statements)

References 21 publications

(1 reference statement)

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“…In their analysis, this effect is due to a jump in the steady strain rate profile, leading to a dramatic increase in the volumetric flow rate. This phenomenon was also observed experimentally by Vinogradov et al [3] in the flow of polymeric fluids through tubes. Similar effects are known in industrial applications, such as injection moulding or extrusion of polymeric melts through a capillary to produce fibres.…”

Section: Introductionsupporting

confidence: 65%

Transient behaviour and stability points of the Poiseuille flow of a KBKZ-fluid

Aarts

Ven

1995

J Eng Math

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The Poiseuille flow of a KBKZ-fluid, being a nonlinear viscoelastic model for a polymeric fluid, is studied. The flow starts from rest and especially the transient phase of the flow is considered. It is shown that under certain conditions the steady flow equation has three different equilibrium points. The stability of these points is investigated. It is proved that two points are stable, whereas the remaining one is unstable, leading to several peculiar phenomena such as discontinuities in the velocity gradient near the wall of the pipe ('spurt') and hysteresis. Our theoretical results are confirmed by numerical calculations of the velocity gradient.

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Section: Introductionsupporting

confidence: 65%

Transient behaviour and stability points of the Poiseuille flow of a KBKZ-fluid

Aarts

Ven

1995

J Eng Math

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“…Vinogradov et al 1972). In this experiment, the flow rate through a capillary is observed to jump dramatically at a critical value of the shear stress, a result that may be attributable to the onset of wall slip.…”

Section: Introductionmentioning

confidence: 73%

Wall slip and the nonlinear dynamics of large amplitude oscillatory shear flows

Graham¹

1995

Journal of Rheology

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SynopsisLarge amplitude oscillatory shear flows of polymer melts between parallel plates may exhibit complicated nonperiodic responses characteristic of quasiperiodicity or chaos. This complex time dependence is related to the wall slip exhibited by these materials. We use simple models for the fluid elasticity and slip to theoretically and computationally study the nonlinear dynamics of melts in oscillatory shear. The results indicate that both fluid elasticity and a dynamic (e.g. memory-slip) model for the wall slip are necessary for nonperiodic dynamics to occur. Furthermore, when elasticity and a dynamic slip model are coupled, many qualitative features of the dynamics observed in the experiments can be reproduced. In particular, asymmetric periodic responses exhibiting even harmonics are found, as well as quasiperiodic and chaotic motions. Particularly interesting is the prediction of multiple stable periodic motions for a given set of parameters, depending on initial conditions. As a special case, the model reduces to the classical Duffing equation of nonlinear vibration theory. The existence of complex dynamics is robust with respect to changes in both the constitutive model chosen and the details of the wall slip model. 0 1995 Society of Rheology.

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“…ture (53)(54)(55)(56)(57). The transition differs from that of the nonisothermal transition associated with heat transfer and heat generation under strain, i.e., two factors common for the whole group of mechanical phenomena covered in this review.…”

Section: Non-lsothermal Phenomena In Polymer Engineering and Science:mentioning

confidence: 99%

Non‐isothermal phenomena in polymer engineering and science: A review. Part II: Non‐isothermal phenomena in polymer deformation

Столин

Merzhanov

Malkin³

1979

Polymer Engineering & Sci

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Perouskii p r . , 35 MOSCOW E-112, U . S . S . R .Thermal phenomena in deformation of solids and flows are reviewed. Regularities common to all these phenomena as well as their characteristic features and consequences important for science and engineering are reported. The analogy between thermal phenomena in polymer mechanics and in chemical reaction is noted. NON-ISOTHERMAL DEFORMATION OF SOLID POLYMERSwhere c0 and uo are strain and stress amplitudes, respectively, with frequency w , 6 is the material characteristic which may be called the angle of mechanical loss. It is characteristic that 6 depends on temperature and frequency, the change of 6 in certain ranges of these parameters being sharp. On passing a region of relaxation (glass transition being the most important) the storage modulus drastically dccreases while mechanical losses are on the increase. A marked change in mechanical properties and, consequently in 6, is also observed at phase transition, if the temperature increase at deformation produces a similar transition.As d 2~ oscillations are performed per unit time the energyA generated per unit time in cyclic deformation is expressed by:where G" characterizes the mechanical properties of viscoelastic bodies and is termed a loss modulus. Data on 6 and G" for various polymers are numerous in the literatnre (see, for example, Ref. 1). It is important to point out thLat G" > 0, i.e., the process ofdeformation is always dissipative.Equations I and 2 are useful for both solid and rubbery substances. The temperature growth here, as in all processes considered, is controlled by heat transfer. The polymer constants for heat generation intensities essentially display a temperature dependence, at least on attaining certain temperatures. This mechanical phenomenon (2-5) is therefore analogous to an exothermal chemical reaction, the analogy extending to the presence of similar critical effects: a thermal explosion in chemical reactions appears analogous to the temperature runawa.y in cyclic deformation which leads to polymer degradation or its inability to resist distortion. In cyclic deformation, various regimes of change in the polymer temperature are possible (2, 6). When heat transfer is sufficiently intensive and the level of operating stresses is limited, heating leads to an equilibrium temperature which depends on the stress amplitude (7).A similar "steady" case, convenient in practice, is a mechanical analogue to an exothermal reaction whose kinetics differ greatly from that of the "thermal explosion" regime. It is reminiscent of a polymerization reaction with relatively weak thermal effects. The analogy is also traced in the termination of the process: (i) the reaction cornes to an end because the reactants are exhausted and (ii) polymer destruction follows.

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Viscoelastic properties and flow of narrow distribution polybutadienes and polyisoprenes

Cited by 195 publications

References 21 publications

Transient behaviour and stability points of the Poiseuille flow of a KBKZ-fluid

Transient behaviour and stability points of the Poiseuille flow of a KBKZ-fluid

Wall slip and the nonlinear dynamics of large amplitude oscillatory shear flows

Non‐isothermal phenomena in polymer engineering and science: A review. Part II: Non‐isothermal phenomena in polymer deformation

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