Linear low density polyethylenes and their blends: Part 1. Molecular characterization

Schlund, B.; Utracki, L. A.

doi:10.1002/pen.760270509

Cited by 47 publications

(14 citation statements)

References 27 publications

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“…The polyethylene resins are difficult to dissolve in 1,2,4-trichlorobenzene at temperatures about their melting point ( 140°C), especially the larger molecules. Moreover, when in solution, the forces developed in the separation columns are large enough (7) to break down these large molecules into smaller parts. As the higher molecular weight moments Mz and Mz+ 1 depend on the molecular weight to the power of 3 and 4 (see Eqs 1 to 51, small variations here will have significant consequences for the accuracy of these parameters.…”

Section: Molecular Structure Definitionmentioning

confidence: 99%

Extrudate swell of high density polyethylene. Part I: Aspects of molecular structure and rheological characterization methods

Koopmans

1992

Polymer Engineering & Sci

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Two high density polyethylene (HDPE) resins–samples 801 and 802–both nominally the same material, as they are taken from successive batches of the same commercial grade, are characterized for their molecular structure and rheological properties. Gel permeation chromatography (GPC) and low angle laser light scattering (LALLS) results must be interpreted in combination with rheological data to show the presence of somewhat more high molecular weight material in 802 that in 801. Small amplitude oscillatory shear, steady shear, and capillary shear measurements performed in different laboratories show consistently higher shear viscosity values at low shear rates for sample 802. Extensional viscosity measurements show similar results. The interpretation of rheological data in terms of molecular structure could be complicated by the possible presence of long chain branching (LCB). The zero shear viscosity and discrete relaxation spectrum is estimated for both samples. The small rheological difference between 801 and 802 forms the basic information for understanding their time dependent extrudate swell behavior, as will be described in Part II.

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Section: Molecular Structure Definitionmentioning

confidence: 99%

Extrudate swell of high density polyethylene. Part I: Aspects of molecular structure and rheological characterization methods

Koopmans

1992

Polymer Engineering & Sci

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“…The rheological property is one of important properties for polymers and sensitive to the miscibility of blends, and it has been used to study the miscibility of blends consisting of different grades of PEs. Some common methods include the Han‐plots, Cole–Cole plots, and Log‐additive composition polts 16–21…”

Section: Introductionmentioning

confidence: 99%

Rheological behaviors and molecular weight distribution characteristics of bimodal high‐density polyethylene

Shen

Luan

Xie

et al. 2011

J of Applied Polymer Sci

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A series of bimodal high density polyethylene (PE) with different molecular weight distributions (MWDs) were prepared by melt blending, and the fitting multipeaks on Gaussian were used to analyze the MWD curves, and the ratio of the areas under unimodal curves was as a tool to characterize the MWD; the phase behaviors and rheological behaviors were studied by dynamic rheological. The results showed that homogeneous bimodal high density PEs could be successfully prepared via melt blending, and the bimodal characteristic could be adjusted as expected. For samples with the MWD peak positions unvaried, the storage modulus, complex viscosity, and zeroshear viscosity decreased rapidly with the value of A L/U increasing. Especially in the low frequency region, the loss modulus surpassed the storage modulus (G 00 > G 0 ) when A L/ U > 10.17 and the dynamic cross-point Gx appeared and increased with increasing A L/U , with an increasing extent much larger than that due to the width of MWD. V C 2011Wiley Periodicals, Inc. J Appl Polym Sci 121: 1543-1549, 2011

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“…For both practical needs in industry and academic interest, a great deal of effort has been devoted to investigating numerous liquid/liquid dispersion systems and an abundance of knowledge has been obtained. The variety of liquid/liquid systems investigated includes Newtonian fluid emulsions,1–4 polymer blends,5–7 and Newtonian/viscoelastic fluid systems 8. Rarely have systems involving low molar mass liquid crystals been investigated.…”

Section: Introductionmentioning

confidence: 99%

Steady viscosity of a polymer/liquid crystal biphasic system

Yang¹,

Lai²

2004

J of Applied Polymer Sci

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Steady shear viscosities of blends of poly(butyl acrylate) and cholesteryl oleyl carbonate were studied under a cone and plate fixture. Unique shear behavior was observed for the polymer/low molar mass liquid crystal mixture. The viscosity of the liquid crystal-rich phase increases with polymer content until a maximum is reached. The height of the viscosity maximum decreases with the magnitude of the shear stress and disappears when the stress reaches 200 Pa. Addition of liquid crystal to the polymer-rich phase causes a viscosity reduction, and at higher stress levels, the viscosity reduction becomes more effective with the same amount of liquid crystal addition. The viscosity reduction may be related to the fibril morphology of the liquid crystal and the viscosity maximum can be interpreted by the emulsion effect being counteracted by a viscosity reduction effect. A shear-thickening behavior was observed in the intermediate shear rates for the blends with a volume fraction of poly(butyl acrylate) between 9.4 and 49.8%. This is a novel liquid-liquid system that exhibits a shear thickening behavior.

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Linear low density polyethylenes and their blends: Part 1. Molecular characterization

Cited by 47 publications

References 27 publications

Extrudate swell of high density polyethylene. Part I: Aspects of molecular structure and rheological characterization methods

Extrudate swell of high density polyethylene. Part I: Aspects of molecular structure and rheological characterization methods

Rheological behaviors and molecular weight distribution characteristics of bimodal high‐density polyethylene

Steady viscosity of a polymer/liquid crystal biphasic system

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