The effect of molar mass distribution on extrudate swell of linear polymers

Doelder, C.F.J. den; Koopmans, R. J.

doi:10.1016/j.jnnfm.2007.04.005

Cited by 10 publications

(7 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similarly, in the recovery phase, a part of the material recovers instantly, another slowly recovers, and a final part does not recover completely, and hence, the polymer remains permanently deformed [28] (Figure 4). In the context of extrudate swelling, a creep and creep recovery experiment is analogous to the events that result therein, hence, the test is more closely related to extrudate swell than any other test measurable in a standard rheometer [29]. From a qualitative perspective, a polymer that displays a larger recovery following removal of the stress will indicate a tendency to exhibit a larger extrudate swelling.…”

Section: Analysing Extrudate Swelling Through Creep Recoverymentioning

confidence: 99%

Polymeric Additive Manufacturing: The Necessity and Utility of Rheology

Elbadawi¹

2018

Polymer Rheology

View full text Add to dashboard Cite

Additive manufacturing techniques have recently seen an explosive growth across a myriad of fields, partly galvanised by their advantages over traditional fabrication techniques. As with most fabrication processes, maximising efficiency is a requisite, particularly if commercialisation is sought-after. Understanding how the material behaves during additive manufacturing is necessary to accomplishing said task. Accordingly, the chapter herein collates examples of where rheology is applicable in polymer-based additive manufacturing techniques, thereby demonstrating the necessity and utility thereto. The main focus herein will be fused deposition modelling and stereolithography additive manufacturing techniques, with examples of how both capillary and rotational rheometers can be utilised.

show abstract

Section: Analysing Extrudate Swelling Through Creep Recoverymentioning

confidence: 99%

Polymeric Additive Manufacturing: The Necessity and Utility of Rheology

Elbadawi¹

2018

Polymer Rheology

View full text Add to dashboard Cite

show abstract

“…This is almost true for extrusion in long capillaries, but for short capillaries, the entry effect figures prominently and entrance effects are relatively numerous and complicated in short-tube flow of polymer melts [1,3,9,11,28,29]. For the case of a short capillary, Liang [11] obtained some semi-empirical quantitative relationships of the swell ratio with material characteristics and operational parameters [30].…”

Section: Introductionmentioning

confidence: 99%

Description of Extrudate Swell for Polymer Nanocomposites

Wang

2010

Materials

View full text Add to dashboard Cite

Extrudate swell is often observed to be weakened in nanocomposites compared to the pure polymer matrix. A theory quantifying this would be significant either for optimum processing or for understanding their viscoelasticity. A unified extrudate swell correlation with material properties and capillary parameters was suggested for polymer melt and their nanocomposites when considering the reservoir entry effect. More importantly, it was the first to find that the composite swell ratio can be the matrix swell ratio multiplied by the concentration shift factor, which is similar to the dynamic moduli expression for composites. The factor is a function of the shear field (stress or shear rate), filler content, filler internal structure and the surface state as well as the matrix properties. Several sets of swell data for nanocomposites were chosen from publications to test the new theories. The proposed quantitative model displayed good fit for the five kinds of nanocomposites, which verified the rationality of the swell theory for nanocomposites.

show abstract

“…He demonstrated that the flow behavior of polydisperse polymers can be better understood by considering the different molecular weight moments of the resin. Recently, Den Doelder and Koopmans unified experimental swell results in terms of specific combinations of higher moments of the molecular weight distribution of the resin [15]. It is also well established that small variations in the die geometry are usually much more effective in altering the swelling characteristics of an HDPE resin than most of the operating parameters.…”

Section: Introductionmentioning

confidence: 99%

A modeling approach to the effect of resin characteristics on parison formation in extrusion blow molding

Yousefi

Doelder

Rainville

et al. 2008

Polymer Engineering & Sci

View full text Add to dashboard Cite

The most critical stage in the extrusion blow-molding process is the parison formation, as the dimensions of the blow-molded part are directly related to the parison dimensions. The swelling due to stress relaxation and sagging due to gravity are strongly influenced by the resin characteristics, die geometry, and operating conditions. These factors significantly affect the parison dimensions. This could lead to a considerable amount of time and cost through trial and error experiments to get the desired parison dimensions based upon variations in the resin characteristics, die geometry, and operating conditions. The availability of a modeling technique ensures a more accurate prediction of the entire blowmolding process, as the proper prediction of the parison formation is the input for the remaining process phases. This study considers both the simulated and the experimental effects of various high-density polyethylene resin grades on parison dimensions. The resins were tested using three different sets of die geometries and operating conditions. The target parison length was achieved by adjusting the extrusion time for a preset die gap opening. The finite element software BlowParison ® was used to predict the parison formation, taking into account the swell and sag. Good agreements were found between the predicted parison dimensions and the experimental data.

show abstract

The effect of molar mass distribution on extrudate swell of linear polymers

Cited by 10 publications

References 33 publications

Polymeric Additive Manufacturing: The Necessity and Utility of Rheology

Polymeric Additive Manufacturing: The Necessity and Utility of Rheology

Description of Extrudate Swell for Polymer Nanocomposites

A modeling approach to the effect of resin characteristics on parison formation in extrusion blow molding

Contact Info

Product

Resources

About