Validation of Cogswell's convergent flow analysis

Revenu, Pascale; Guillet, Jacques; Carrot, Christian; Arsac, A.

doi:10.1002/(sici)1097-4628(19961212)62:11<1783::aid-app2>3.0.co;2-m

Cited by 12 publications

References 6 publications

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Application of a linear synthetic polymer to improve the properties of cellulose fibers made by the NMMO process

Lewandowski

2002

J of Applied Polymer Sci

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Low-molecular polyethylene (LMPE) as an internal flexibilizer was selected to improve the spinnability of cellulose solution in N-methylmorpholine-N-oxide (NMMO). It is compatible with the conditions of cellulose dissolution and fiber spinning because of its chemical stability and melting point. In the course of rheological investigations, it was proven that this modification has a physical characteristic. Cross sections of the fibers reveal that cellulose-LMPE forms a two-phase system with randomly distributed LMPE domains and a dominant skin-core structure. The addition of 5% LMPE is enough to improve significantly the mechanical properties of the fibers. An increase of LMPE above 5% worsens these properties, because LMPE is not a fiber-forming polymer. With the use of spinnerets with suitable dimensions, it is possible to obtain cellulose fibers with mechanical properties similar to those of synthetic fibers. The retention of water is lowered by the hydrophobic polyethylene polymer; however, it is high enough to retain the hydrophilic character of cellulose fibers.

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Application of a linear synthetic polymer to improve the properties of cellulose fibers made by the NMMO process

Lewandowski

2002

J of Applied Polymer Sci

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Gross melt fracture of polyethylene. I: A criterion based on tensile stress

Kim

Dealy

2002

Polymer Engineering & Sci

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We propose the use of a critical tensile stress as a criterion for the onset of gross melt fracture (OGMF). This stress is estimated from the entrance pressure drop using the method of Cogswell. Carbon black tracer was used to verify that what we deemed to be GMF, based on the inspection of extrudate, was indeed the result of a brittle rupture. An orifice die was used to eliminate the complications arising from the presence of a capillary. Polyethylenes having a variety of molecular structures were used to evaluate the usefulness of the uitical tensile stress for characterizing polymers. The critical stress was found to be independent of temperature and contraction ratio. It is also independent of entrance angle, as long as this is equal to or greater than 90 degrees. The critical stress is thus a material property and can be used to rate the tendency of polymers to exhiiit gross melt fracture.

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Interfacial slip‐stick transition induced by reactive compatibilization in ethylene‐co‐butyl acrylate elastomer dispersed polyamide 6 blend subjected to high shear flow and extensional flow

Balamurugan¹,

Maiti²

2008

Polymer Engineering & Sci

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The effect of phase interaction induced by reactive compatibilization during high shear and extensional flow in polyamide (PA6) and ethylene‐co‐butyl acrylate (EBA) blends was studied using advanced dual bore capillary rheometer. The viscosity‐composition behavior of the uncompatibilized PA6/EBA blends exhibited negative deviation behavior from log‐additivity rule. The interfacial slip mechanism, operative between the matrix PA6 and dispersed EBA during shear flow was studied by the use of Lin's and Bousmina‐Palierne‐Utracki (BPU) model for viscosity for the blends under the processing conditions. On the other hand, the compatibilized PA6/EBA‐g‐MAH0.49/EBA blends with varying dispersed phase volume fraction show positive deviation behavior. The reactive compatibilizers EBA‐g‐MAH0.49 and EBA‐g‐MAH0.96 increased the phase interaction with adequate reduction in the dynamic interfacial tension, which favored the particle break‐up and stabilized the morphology in the compatibilized blends. The extensional viscosity of the blends has enhanced because of the inclusion of EBA in all the uncompatibilized and compatibilized blends. The melt elasticity and elasticity function were systematically studied from first normal stress coefficient functions (ψ1). The variation in the recoverable shear strain (γR), shear rate dependent relaxation time (λ) and shear compliance (Jc) under various shear rates were thoroughly analyzed for all the blend compositions. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers

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Validation of Cogswell's convergent flow analysis

Cited by 12 publications

References 6 publications

Application of a linear synthetic polymer to improve the properties of cellulose fibers made by the NMMO process

Application of a linear synthetic polymer to improve the properties of cellulose fibers made by the NMMO process

Gross melt fracture of polyethylene. I: A criterion based on tensile stress

Interfacial slip‐stick transition induced by reactive compatibilization in ethylene‐co‐butyl acrylate elastomer dispersed polyamide 6 blend subjected to high shear flow and extensional flow

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