Comparison between slit viscometry and cylindrical capillary viscometry

Wales, J. L. S.; Otter, J. L. den; Janeschitz‐Kriegl, H.

doi:10.1007/bf01984712

Cited by 42 publications

(10 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The viscosity of a polymer melt can be calculated using the following equations:31–33 where L is the length of the die, W is the slit width, H is the slit height, Q is the volumetric flow rate, and Δ P is the pressure drop. To obtain viscosity measurements at constant CO 2 concentrations, calibration of the mass flow rate is required.…”

Section: Experimental Materials and Methodsmentioning

confidence: 99%

High‐pressure rheology and viscoelastic scaling predictions of polymer melts containing liquid and supercritical carbon dioxide

Royer

DeSimone

Khan

2001

J Polym Sci B Polym Phys

View full text Add to dashboard Cite

High-pressure rheological behavior of polymer melts containing dissolved carbon dioxide (CO 2 ) at concentrations up to 6 wt % were investigated using a highpressure extrusion slit die rheometer. In particular, the steady shear viscosity of poly(methyl methacrylate), polypropylene, low-density polyethylene, and poly(vinylidene fluoride) with dissolved CO 2 were measured for shear rates ranging from 1 to 500 s Ϫ1 and under pressure conditions up to 30 MPa. The viscosity of all samples revealed a reduction in the presence of CO 2 with its extent dependent on CO 2 concentration, pressure, and the polymer used. Two types of viscoelastic scaling models were developed to predict the effects of both CO 2 concentration and pressure on the viscosity of the polymer melts. The first approach utilized a set of equations analogous to the Williams-Landel-Ferry equation for melts between the glass-transition temperature (T g ) and T g ϩ 100°C, whereas the second approach used equations of the Arrhenius form for melts more than 100°C above T g . The combination of these traditional viscoelastic scaling models with predictions for T g depression by a diluent (Chow model) were used to estimate the observed effects of dissolved CO 2 on polymer melt rheology. In this approach, the only parameters involved are physical properties of the pure polymer melt that are either available in the existing literature or can be measured under atmospheric conditions in the absence of CO 2 . The ability of the proposed scaling models to accurately predict the viscosity of polymer melts with dissolved high-pressure CO 2 were examined for each of the polymer systems.

show abstract

Section: Experimental Materials and Methodsmentioning

confidence: 99%

High‐pressure rheology and viscoelastic scaling predictions of polymer melts containing liquid and supercritical carbon dioxide

Royer

DeSimone

Khan

2001

J Polym Sci B Polym Phys

View full text Add to dashboard Cite

show abstract

“…The viscosity of a polymer melt can be calculated using the following equations:24–26 where L is the length of the die, W the slit width, H the slit height, Q the volumetric flow rate, and Δ P the pressure drop. To obtain viscosity measurements at constant CO 2 concentrations, calibration of the mass flow rate is required.…”

Section: Experimental Materials and Methodsmentioning

confidence: 99%

Ophthalmic delivery of sparfloxacin from in situ gel formulation for treatment of experimentally induced bacterial keratitis

Nesseem

2010

Drug Testing and Analysis

View full text Add to dashboard Cite

The objective of the present work was (1) to develop an in situ gelling ophthalmic delivery system by combining pluronic F127 and pluronic F68, with sparfloxacin; and (2) to examine the influence of incorporating a mucoadhesive polysaccharide such as sodium hyaluronate on the healing property due to bacterial keratitis. The formulations (F1-F6) were sterilized by gamma irradiated using Co(60) . Ultraviolet (UV) and infrared (IR) spectra studies were performed on sterilized and non-sterilized formulae. The formulations were evaluated for rheological characteristics, in vitro release behavior, and efficacy against induced bacterial conjunctivitis in rats' eyes. Moreover, histopathological evaluations were also done. All the samples passed sterility tests, and no change in physical appearance of the formulae due to gamma radiation was observed. The IR spectra of the formulae before and after sterilization showed similar peaks which confirmed that no ingredient was affected by gamma radiation. The formulations showed a flow index of 0.116-0.493 indicating pseudoplastic flow behavior. The release behavior of all formulae was non-Fickian anomalous release. The different formulae used to overcome the pathological alterations, produced by bacteria infections varied among each other depending on the duration of treatment; however, the effectiveness of formulation was arranged as F5, F4 and F3, respectively. The developed formulations were therapeutically efficacious, and provided sustained release of the drug over a 24-hour period. A better improvement in artificially induced bacterial conjunctivitis in rats' cornea was observed with the developed formulae; thus it can be considered as a viable alternative to conventional eye drops.

show abstract

“…(3)) considers the fact that the shear rate mentioned in Eq. (2) is only valid for Newtonian fluids and provides the true shear rate at the capillary wall for them [22].…”

Section: Round Diementioning

confidence: 99%

“…(8)) adjusts the shear rate at the wall for the non-Newtonian liquids. The true shear rate at the wall for a slit die ( γ ̇ □ ) is calculated by [22]:…”

Section: Slit Diementioning

confidence: 99%

Rheology of Highly Filled Polymers

Kukla¹,

Đuretek²,

González-Gutiérrez³

et al. 2018

Polymer Rheology

View full text Add to dashboard Cite

In many applications and/or manufacturing processes, highly filled polymers are necessary. One of these fields is powder metallurgy, where polymers or polymer mixtures are used to enable the shaping process within the production of the parts. Metal and also ceramic powders are mixed with different polymeric substances with a powder content of more than 50 vol%. Within the production, this mixture, called feedstock, has to flow into the final shape. Thus, for a proper understanding of the production processes, fundamental knowledge on the flow behavior of the feedstocks is required. For the rheology of polymers, several techniques together with the proper equipment are available. In the case of high viscosities, rotational and high-pressure capillary rheometers (HPCRs) are used. To gain reliable data, a proper measurement procedure is essential, which means that the operator has to have a deeper physical understanding of the material and the effects arising during the measurements. Therefore, this chapter gives an insight into rotational and high-pressure capillary rheometry with special emphasis on the behavior of polymers highly filled with stiff particles. Based thereon important remarks on the measurement equipment, procedure and evaluation of the measured data are provided.

show abstract

Comparison between slit viscometry and cylindrical capillary viscometry

Cited by 42 publications

References 7 publications

High‐pressure rheology and viscoelastic scaling predictions of polymer melts containing liquid and supercritical carbon dioxide

High‐pressure rheology and viscoelastic scaling predictions of polymer melts containing liquid and supercritical carbon dioxide

Ophthalmic delivery of sparfloxacin from in situ gel formulation for treatment of experimentally induced bacterial keratitis

Rheology of Highly Filled Polymers

Contact Info

Product

Resources

About