The weissenberg effect in molten polymers
WebThe viscosity of a polymer melt varies with the weight average molecular weight M w to the power of ~3.4. In polymer processing the Melt Flor Rate, or MFR, is used to characterize a polymer melt. Whereas the MFR (Figure 3) is a very common measurement, it is not a pure measurement of viscosity. Off-spec material can be easily blended to make a ... WebSep 16, 2008 · Do the Weissenberg effect science experiment. When a rod mounted in a hand drill is dipped into a liquid and rotated, for certain non-Newtonian fluids the liquid will climb the rod - sometimes to quite spectacular heights. Such rob climbing behaviour is referred to as the Weissenberg Effect. Shearing in the flow of the liquid concentrically ...
The weissenberg effect in molten polymers
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WebWeissenberg Effect The Weissenberg Effect is the instance where a polymer travels up a rod, in contrast to say water that moves away from the rod as it spins. By considering the … WebThe effects of factors such as shear rate, molecular weight distribution, pressure, filler, temperature and additives on viscosity are summarized in Figure 1.5, following Cogswell …
WebInvestigations of polymer mixtures permit the study of the deformation and interaction of polymer structures at temperatures well below the melting point. By means of the … WebWhen a rotating rod is immersed in a molten polymer or a fairly concentrated polymer solution, the liquid will actually climb up the rod. This phenomenon, the Weissenberg effect, is contrary to what is observed in nonpolymer liquids, which ... polymers have only a few organic functional groups, that repeat over and over to make the ...
WebAug 31, 1998 · Using published experimental data for N 1 (σ) and N 2 (σ) to evaluate R, we find that positive Weissenberg effects are predicted for polyisobutylene and some … WebThis phenomenon is familiar to investigators of artificial high polymers as the Weissenberg effect 1–3, which is usually observed where the macromolecules or other structures form …
WebMay 30, 2024 · Thus, the Weissenberg Effect is the instance in which a polymer travels up a rod as it spins, in contrast to say water that moves away from the rod as it spins. Why …
WebThe "Weissenberg Effect" or "Rod-Climbing Experiment" In this video clip a dilute (0.025 wt%) solutionof a high molecular weight (2×10 6 g/mol) polystyrene polymer (Polysciences Inc) is dissolved in a low molecular weight (~100 g/mol) newtonian viscous (~30 Pa.s) solvent (Piccolastic, Hercules Inc). In the experiment a rod is rotated with its end immersed in the … boss day quotesWebdetailed to explain some of the unusual behavior of polymers. Four different effects will be covered; Weissenberg, Barus, Kaye, and a defying gravity experiment. Students will then … hawes curtis canary wharfWebIt is also assumed that there are no temperature gradients within the coalescing molten polymers (lumped parameter heat transfer analysis). Findings – The models predict faster sintering with... hawes cumbriaWebAnother well-known phenomenon is the Weissenberg effect, which occurs when a long vertical rod is rotated in a viscoelastic liquid. Again, the shearing generates a tension along the streamlines, which are circles centred on the axis of the rod. boss dentistryWebOver ranges of shear rate experimentally accessible for molten polymers, we find that R>0 provided that ɛ>1/8. When ɛ=0, however, we find that R<0 for most low-to-moderate shear … boss design artur witczakWebApr 14, 2024 · Synthetic polymers shape our contemporary way of life, from packaging to medical masks and numerous other applications. 1 However, the effects of cumulative plastic pollution on soil, atmosphere, and marine ecosystems have become extremely severe, affecting everyday lives, and are a legitimate threat to future generations. 2 It is … boss dental pc flushingWebJul 1, 2024 · In his celebrated article entitled “A continuum theory of rheological phenomena”, Weissenberg [ 1] reported the so-called rod-climbing phenomenon in laminar flow of a visco-elastic fluid, a popular phenomenon that can be observed in daily life when one stirs a bowl of cake batter or a can of paint—though, interestingly, this phenomenon … hawes cutting act