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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
provided by the
Networked Digital Library of Theses and Dissertations.
Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Showing 1 to 4 of 4 (0.064 seconds)Spelling suggestions: "subject:"low birefringence"" "subject:"flow birefringence""
| 1 |
Processing of polypropylene by melt transformation extrusion process, study of flow birefringence, using an internally cooled dieGhosh, Jayanto K. January 1984 (has links)
No description available.
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| 2 |
INJECTION-COMPRESSION AND CO-INJECTION MOLDINGS OF AMORPHOUS POLYMERS: VISCOELASTIC SIMULATION AND EXPERIMENTKim, Nam Hyung 09 June 2009 (has links)
No description available.
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| 3 |
Processing of polypropylene by melt transformation coextrusion process, study of flow birefringence, using an internally cooled dieSierra-Irizarry, Eddie A. January 1987 (has links)
No description available.
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| 4 |
SHEAR RHEOMETRY PROTOCOLS TO ADVANCE THE DEVELOPMENT OF MICROSTRUCTURED FLUIDSEduard Andres Caicedo Casso (6620462) 15 May 2019 (has links)
<p></p><p>This doctoral dissertation takes the reader through a
journey where applied shear rheology and flow-velocimetry are used to
understand the mesoscopic factors that control the flow behavior of three
microstructured fluids. Three individual protocols that measure relative
physical and mechanical properties of the flow are developed. Each protocol
aims to advance the particular transformation of novel soft materials into a
commercial product converging in the demonstration of the real the chemical,
physical and thermodynamical factors that could potentially drive their
successful transformation. </p>
<p> </p>
<p>First, this dissertation introduces the use of rotational
and oscillatory shear rheometry to quantify the solvent evaporation effect on
the flow behavior of polymer solutions used to fabricate isoporous asymmetric
membranes. Three different A-B-C triblock copolymer were evaluated:
polyisoprene-<i>b</i>-polystyrene-<i>b</i>-poly(4-vinylpyridine) (ISV);
polyisoprene-<i>b</i>-polystyrene-<i>b</i>-poly(<i>N</i>,<i>N</i>-dimethylacrylamide)
(ISD); and polyisoprene-<i>b</i>-polystyrene-<i>b</i>-poly(<i>tert</i>-butyl methacrylate) (ISB). The resulting evaporation-induced
microstructure showed a solution viscosity and film viscoelasticity strongly
dependent on the chemical structure of the triblock copolymer molecules. </p>
<p> </p>
<p>Furthermore, basic shear rheometry, flow birefringence, and
advanced flow-velocimetry are used to deconvolute the flow-microstructure relationships
of concentrated surfactant solutions. Sodium laureth sulfate in water (SLE<sub>1</sub>S)
was used to replicate spherical, worm-like, and hexagonally packed micelles and
lamellar structures. Interesting findings demonstrated that regular features of
flow curves, such as power-law shear thinning behavior, resulted from a wide
variety of experimental artifacts that appeared when measuring microstructured
fluids with shear rheometry.</p>
<p> </p>
<p>Finally, the successful integration of shear rheometry to
calculate essential parameters to be used in a cost-effective visualization
technique (still in development) used to calculate the dissolution time of
polymers is addressed. The use of oscillatory rheometry successfully quantify
the viscoelastic response of polyvinyl alcohol (PVA) solutions and identify
formulations changes such as additive addition. The flow behavior of PVA
solutions was correlated to dissolution behavior proving that the developed
protocol has a high potential as a first screening tool.</p><br><p></p>
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