Extrusion of Polymer Melts and Melt Flow Instabilities. I. Experimental Study of Capillary Flow and Extrudate Distortion

1969 ◽  
Vol 42 (3) ◽  
pp. 675-681 ◽  
Author(s):  
Gene A. Bialas ◽  
James L. White
Keyword(s):  
Experimental Data ◽  
Polymer Melts ◽  
Capillary Flow ◽  
Flow Instability ◽  
Research Effort ◽  
Flow Instabilities ◽  
Melt Flow ◽  
Considerable Research ◽  
Extrudate Distortion ◽  
First Descriptions

Abstract The extrusion of molten plastics, elastomers and fibers represent an important industrial operation. The rate of extrusion of melts through dies is limited by the onset of a flow instability. This phenomenon consists of a change in flow from uniform to irregular that results in the production of rough and distorted extradates drastically different from the smooth cylinders obtained at lower rates. Extrusion melt flow instability is observed in the entire spectrum of polymer melts ranging from silicone gums through nylon and polyolefin plastics to raw elastomers. Since the first descriptions of this phenomena in the 1940's considerable research effort has been expended in this area with limited agreement. It is the purpose of part I to: (1) present new experimental data on capillary flow of polymer melts and extrudate distortion, and (2) to review critically the literature on extrudate distortion.

Extrusion of Polymer Melts and Melt Flow Instabilities. II. Site of Initiation and Mechanism of Melt Flow Instability

1969 ◽  
Vol 42 (3) ◽  
pp. 682-690 ◽  
Author(s):  
Gene A. Bialas ◽  
James L. White
Keyword(s):  
Experimental Data ◽  
Flow Regime ◽  
Polymer Melts ◽  
Flow Instability ◽  
Experimental Studies ◽  
Flow Instabilities ◽  
Critical Survey ◽  
Melt Flow ◽  
Unstable Flow

Abstract In the second part of this paper we will make a critical survey of experimental studies on the site of initiation, the structure of the unstable flow regime, criteria for the inception of the instability and mechanisms for initiation of the unstable flow regime. Some new experimental data will be cited in the discussion of criteria.

Melt flow instabilities in capillary flow of two-phase polymer systems

1972 ◽  
Vol 12 (2) ◽  
pp. 77-80 ◽  
Author(s):  
C. D. Han ◽  
R. R. Lamonte
Keyword(s):  
Capillary Flow ◽  
Flow Instabilities ◽  
Melt Flow ◽  
Two Phase ◽  
Polymer Systems

Capillary flow instability of ethylene polymer melts

1970 ◽  
Vol 10 (4) ◽  
pp. 193-203 ◽  
Author(s):  
L. L. Blyler ◽  
A. C. Hart
Keyword(s):  
Polymer Melts ◽  
Capillary Flow ◽  
Flow Instability ◽  
Ethylene Polymer

Wall slip and absence of interfacial flow instabilities in capillary flow of various polymer melts

1998 ◽  
Vol 42 (1) ◽  
pp. 63-80 ◽  
Author(s):  
Xiaoping Yang ◽  
Hatsuo Ishida ◽  
Shi-Qing Wang
Keyword(s):  
Polymer Melts ◽  
Capillary Flow ◽  
Wall Slip ◽  
Flow Instabilities ◽  
Interfacial Flow

Capillary flows and self-assembly of porous hydrate structures

2012 ◽  
Vol 9 (1) ◽  
pp. 22-25
Author(s):  
S.V. Amel’kin ◽  
D.Ye. Igoshin
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Self Assembly ◽  
Capillary Flow ◽  
Secondary Crystallization ◽  
Assembly Model ◽  
Physical Processes ◽  
Good Correspondence ◽  
Solution Formation ◽  
Capillary Flows

A self-assembly model for porous hydrate structures is proposed, which takes into account the sequence of basic physical processes: hydrate growth on the surface of the aqueous solution, formation of islet structure, capillary flow, separation and transfer of secondary crystallization nuclei to the meniscus. The model was studied within the cellular automata method. A good correspondence between the results of the simulation and the experimental data is obtained.

scholarly journals Analgesia for Sheep in Commercial Production: Where to Next?

Animals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1127
Author(s):  
Alison Small ◽  
Andrew David Fisher ◽  
Caroline Lee ◽  
Ian Colditz
Keyword(s):  
Research Effort ◽  
Mitigation Strategies ◽  
Worth Living ◽  
Life Worth Living ◽  
The Past ◽  
Considerable Research ◽  
Husbandry Practices ◽  
Industry Practice ◽  
Successful Launch ◽  
Inflammatory Drugs

Increasing societal and customer pressure to provide animals with ‘a life worth living’ continues to apply pressure on livestock production industries to alleviate pain associated with husbandry practices, injury and illness. Over the past 15–20 years, there has been considerable research effort to understand and develop mitigation strategies for painful husbandry procedures in sheep, leading to the successful launch of analgesic approaches specific to sheep in a number of countries. However, even with multi-modal approaches to analgesia, using both local anaesthetic and non-steroidal anti-inflammatory drugs (NSAID), pain is not obliterated, and the challenge of pain mitigation and phasing out of painful husbandry practices remains. It is timely to review and reflect on progress to date in order to strategically focus on the most important challenges, and the avenues which offer the greatest potential to be incorporated into industry practice in a process of continuous improvement. A structured, systematic literature search was carried out, incorporating peer-reviewed scientific literature in the period 2000–2019. An enormous volume of research is underway, testament to the fact that we have not solved the pain and analgesia challenge for any species, including our own. This review has highlighted a number of potential areas for further research.

Viscosity Models Based on Network Theory for Polymer Melts

2010 ◽  
Vol 129-131 ◽  
pp. 1244-1247
Author(s):  
Hai Hang Xu ◽  
Lei Zhong
Keyword(s):  
Experimental Data ◽  
Kinetic Equation ◽  
Constitutive Equation ◽  
Polymer Composites ◽  
Network Theory ◽  
Polymer Melts ◽  
Structure Parameter ◽  
Viscosity Models ◽  
Model Predictions ◽  
Good Agreement

New shear and extensional viscosity models based on Fredrickson kinetic equation coupled with Dewitt constitutive equation were established to predict viscosities of polymer melts. The experimental data of 125°C LDPE and LDPE filled with 35% glass beads reported from references were compared with the model predictions. The predictions showed good agreement with the measurements. The models are simple and easy to use. Because they contain no structure parameter, they are capable to describe the viscosities of pure polymer and polymer composites.

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