Prediction of high density polyethylene processing behavior from rheological measurements

Shida, Mitsuzo; Cancio, L. V.

doi:10.1002/pen.760110207

Cited by 21 publications

(9 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At higher shear rates it is a decreasing function. For the PP-H-R-B and PP-H-B-R, 7, could not be determined and was estimated using Sabia's equation (31,32).…”

Section: Shear Viscositymentioning

confidence: 99%

Experimental investigation of the influence of molecular weight distribution on the rheological properties of polypropylene melts

Minoshima¹,

White²,

Spruiell³

1980

Polymer Engineering & Sci

136

View full text Add to dashboard Cite

An experimental study of steady shear and elongational flow Theological properties of a series of polypropylene melts of varying molecular weight and distribution is reported. Broadening the molecular weight distribution increases the non‐Newtonian character of the shear viscosity function and increases the principal normal stress differences at fixed shear stress. The behavior is compared to earlier rheological property‐molecular weight studies. Correlations are developed for these properties in terms of molecular structure. Elongational flow studies indicate that for commercial and broader molecular weight distribution samples, ready failure by neck development occurs and the elongational viscosity appears to decrease with increasing elongation rate. For narrower molecular weight distribution samples, the elongational viscosity is an increasing function of elongation rate, The implication of these experimental results to viscoelastic fluid constitutive equations and polymer melt processing is developed.

show abstract

“…At higher shear rates it is a decreasing function. For the PP-H-R-B and PP-H-B-R, 7, could not be determined and was estimated using Sabia's equation (31,32).…”

Section: Shear Viscositymentioning

confidence: 99%

Experimental investigation of the influence of molecular weight distribution on the rheological properties of polypropylene melts

Minoshima¹,

White²,

Spruiell³

1980

Polymer Engineering & Sci

136

View full text Add to dashboard Cite

show abstract

“…21 This suggests that the polymer with wider MWD obtained by the sequential addition was separated into Flory distributions as shown in Figure 3, and the fraction of Flory distributions of catalyst systems can be processed more easily. 22 from EIZ (peak V) and MgCl 2 -Ti catalyst (peaks I-VI) was obtained. In the case of peak V, Flory distributions from EIZ and MgCl 2 -Ti catalyst CONCLUSION were mixed.…”

Section: Of Eiz/mao and Mgcl 2 -Ti/tea Catalyst Systemsmentioning

confidence: 99%

Control of molecular weight distribution in propylene polymerization with Ziegler-Natta/metallocene catalyst mixtures

Ahn

Hong

Kim

et al. 1998

J. Appl. Polym. Sci.

View full text Add to dashboard Cite

Propylene polymerization was investigated with a sequential addition of Ziegler-Natta and metallocene catalysts. From the fact that the molecular weights of polypropylene (PP) produced with Ziegler-Natta and with metallocene catalysts differ, it was possible to control the molecular weight distribution (MWD) of PP with a sequential addition of methylaluminoxane and rac-ethylenebis(indenyl)zirconium dichloride followed by triethylaluminum and magnesium dichloride-supported titanium tetrachloride catalyst. The obtained PP exhibited a wide MWD curve with shoulder peak. The position and height of each peak was controlled with the variation of polymerization time for each catalyst as well as the amount of each catalyst. The MWD of PP prepared with sequential addition of catalysts was much wider than that of PP obtained from each catalyst.

show abstract

“…The melt flow index is itself insensitive to subtle changes in molecular parameters, as has been shown by Smith: Borzen~ki,~ and Shida and Cancio. 8 Since MFI has been used as a normalizing factor during coale~cence,'-~ the unified curves, too, are insensitive to changes in molecular weight distribution. The effects of differences in molecular weight distribution are seen in the low shear rate and very high shear rate region.…”

Section: Introductionmentioning

confidence: 99%

Upgrading the melt flow index to rheogram approach in the low shear rate region

Shenoy

Saini

1984

J of Applied Polymer Sci

View full text Add to dashboard Cite

SynopsisThe unified viscosity function curves proposed earlier by the authors have an inherent limitation in the low shear rate region. This limitation is the effect of using the melt flow index as a normalizing factor to obtain the coalesced curves, which itself is insensitive to molecular parameters such as molecular weight distribution. A single integral constitutive equation of the BKZ type is used to derive the viscosity function which would be useful in generating unified curves based on the melt flow index but devoid of the limitation of molecular weight distribution effects in the low shear rate region.

show abstract

Prediction of high density polyethylene processing behavior from rheological measurements

Cited by 21 publications

References 9 publications

Experimental investigation of the influence of molecular weight distribution on the rheological properties of polypropylene melts

Experimental investigation of the influence of molecular weight distribution on the rheological properties of polypropylene melts

Control of molecular weight distribution in propylene polymerization with Ziegler-Natta/metallocene catalyst mixtures

Upgrading the melt flow index to rheogram approach in the low shear rate region

Contact Info

Product

Resources

About