Correlation between melt fracture and ultrasonic velocity

Herranen, Mika; Savolainen, Antti

doi:10.1007/bf01329201

Cited by 10 publications

(4 citation statements)

References 3 publications

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“…The considerable practical importance of plasticized poly(vinyl chloride) (PVC)-based compounds in the field of cables' insulation adds value to their rheological study [1,2]. As expected, it was observed that the addition of various compounds to the main polymer modifies the rheological properties to a considerable extent [2][3][4].…”

Section: Introductionmentioning

confidence: 65%

Influence of the Stabilization System on the Rheological Behaviour of Plasticized PVC for Cables’ Insulation

Petraru¹,

Popa²

2017

Eurasian Chem. Tech. J.

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The paper is devoted to the rheological study of plasticized PVC - based compositions for cables’ insulation, stabilized with three different systems (Ba laurate/Cd laurate, Sn dibutyl mercaptide, Pb bibasic stearate/Pb bibasic fosfite) in variable ratios. Starting from some measured parameters, several rheological properties - characteristic for the viscous and, respectively, elastic component of flowing - have been calculated (counter pressure, worm gear’s rotation moment, shear stress at the wall, apparent viscosity, standard viscosity and the viscosity index, output pressure from the rheological nozzle, swelling, relaxation time, first function of the normal unitary stresses, index of elasticity). The observation to be made is that the system of thermal stabilization influences strongly the rheological behaviour by both its nature and amount, which requires a careful consideration of the effects, when products of different types are to be designed. The best thermal stabilization is assured by the Pb bibasic stearate/Pb bibasic fosfite - based system. The obtained recipes have been subsequently characterized from the viewpoint of their thermal stability and, equally, of some of their electrical properties. It was observed that the system of thermal stabilization strongly influences the thermal stability as well as the electrical properties of the plasticized PVC recipes. The highest values of thermal stability, which correlated with corresponding electrical properties, have been attained for the Pb- based system. When different stabilization systems are employed, the transparent, translucent or opaque insulations may be obtained.

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Section: Introductionmentioning

confidence: 65%

Influence of the Stabilization System on the Rheological Behaviour of Plasticized PVC for Cables’ Insulation

Petraru¹,

Popa²

2017

Eurasian Chem. Tech. J.

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“…Perez et al found that blends containing a large amount of LDPE show gross melt fracture, whereas blending a small amount of LDPE can postpone the shark-skin failure for LLDPE [48]. Herranen and Savolainen also reported that addition of LDPE reduces the onset shear rate of shark-skin failure for LLDPE [49]. However, in many cases of the study on the flow instability for blends of LLDPE and LDPE, less attention has been paid on the anomalous rheological response such as marked melt elasticity to the best of our knowledge.…”

Section: Introductionmentioning

confidence: 92%

“…Since it is generally accepted that a high viscous polymer melt slips on the wall, the slippage can be the origin of surface instability [35,43,44]. Gross melt fracture is attributed to the flow instability at a die entrance, and associated with long time relaxation mechanism [38,[45][46][47][48][49][50][51]. Yamaguchi et al found that gross melt fracture of LDPE can be avoided by applying intense shear history, which weakens the relaxation mechanism associated with long-chain branches, by shear modification [51].…”

Section: Introductionmentioning

confidence: 99%

Flow instability for binary blends of linear polyethylene and long-chain branched polyethylene

Mieda

Yamaguchi

2011

Journal of Non-Newtonian Fluid Mechanics

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“…Generally, an increase in temperature postpones its onset to higher flow rates (Herrainen and Savolainen, 1984;Beaufils et al, 1989). It has been shown that a master curve can be obtained by plotting the amplitude or the period of the defect as function of the reduced stress, i. e. the product of the stress at the wall by T/T0, T0 being a reference temperature Venet and Vergnes, 1997;Rutgers and Mackley, 2000) (Fig.…”

Section: Influence Of Parametersmentioning

confidence: 99%

Extrusion Defects and Flow Instabilities of Molten Polymers

Vergnes

2015

International Polymer Processing

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International audienceWhen certain critical conditions are exceeded, the flow of a polymer melt becomes unstable, giving rise to particular phenomena that are the subject of this review. These instabilities are a vital industrial problem, as they are the key to productivity of extrusion processes. Indeed, their onset leads to unacceptable products and is thus the upper limit of the processing conditions. They are also a fascinating scientific problem because, although studied and discussed for more than half a century, they are still not fully understood and their mechanisms are still sometimes controversial. In the present literature review, we present an overview of the studies carried out for fifty years, as well as our own opinion on the underlying mechanisms.3-2

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Correlation between melt fracture and ultrasonic velocity

Cited by 10 publications

References 3 publications

Influence of the Stabilization System on the Rheological Behaviour of Plasticized PVC for Cables’ Insulation

Influence of the Stabilization System on the Rheological Behaviour of Plasticized PVC for Cables’ Insulation

Flow instability for binary blends of linear polyethylene and long-chain branched polyethylene

Extrusion Defects and Flow Instabilities of Molten Polymers

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