High-density polyethylene rheological properties

For high density polyethylene the MWD represents one of the basic parameters which, together with average molecular weight, density, short and long chain branching content, determines the physical, mechanical and rheological properties of the polymer and therefore its end uses (Table 1). 

Studies on the morphology and on the melt rheological, tensile, and impact properties were carried out on ternary blend of iPP with two of the following polymers low and high density polyethylene, styrene-b-ethylene butylene-b-styrene triblock copolymer, polystyrene, and acrylonitrile-butadiene-styrene terpolymer (30-33). The results are interpreted for the effect of each individual component by comparing the ternary blends with the respective iPP-based binary blends as the reference systems. 

In order to improve properties and compatibility of PP/EPDM blends, ternary blends and composites are sometimes prepared from the PP/EPDM blends. For instance, Sanchez et al. (10) prepared ternary blends of PP, high density polyethylene and EPDM with several blending ratios and investigated the melt rheological behaviors. They discussed the effect of the shear rate on the viscosity and flow curve in terms of the exponent of low power for a non-Newtonian liquid. They showed that addition of an elastomer to the polyolefin blends changes the shape of the viscosity-composition curve, and they discussed it in terms of the possible morphology of the blend. Similar works have been also reported by Ha et al. (11,12). 

S. Siengchin, T.N. Abraham, Morphology and rheological properties of high density polyethylene/fluorothermoplastics blends. J. Appl. Polym. Sci. 127, 919-925 (2013)... 

Lu JK, Ke YC, Qi ZN, Yi XS (2001) Studies of intercalation and exfoliation behavior of organoclays in epoxy resin. J Poym Sci Part B Polym Phys 39 115-120 Lotti C, Isaac CS, Branciforti MC, Alves RMV, Liberman S, Bretas RES (2008) Rheological, mechanical and transport properties of blown films of high density polyethylene nanocomposites. Eur Polym J 44 1346-1357... 

In order to improve the tensile properties of low-density polyethylene. Mead and Porter [100] added high density polyethylene fibers and film strips. This resulted in an increase in the extensional viscosity and consequently, the tensile modulus of the composite was increased by a factor of 10. The effect of different mineral fillers (e.g. talc, mica, clay, dolomite) on the rheological properties of low density polyethylene films was studied by Arina et al. [17]. It was found that the fillers increased the extensional viscosity of a polymer matrix in concurrence with the earlier observations of Han and Kim [86] as well as Mead and Porter [100]. 

Chen, G., Guo, S., and Li, Y. (2004) Dynamic rheological properties of high-density polyethylene/polystyrene blends extruded in the presence of ultrasonic oscillations./. Appl Polym. Scl, 92, 3153-3158. 

Winter, H. H., A collaborative study on the relation between film blowing performance and rheological properties of two low-density and two high-density polyethylene samples. Pure Appl Chem., 55, 943-976 (1983). 

Rongxian Oua, Yanjun Xiea, Michael P. Wolcott, Feipin Yuana, Qingwen Wang. Effect of wood cell wall composition on the rheological properties of wood particle/high density polyethylene composites. Compos. Sci. Technol. 93,68-75 (2014). 

W. Minoshima and J. L. White, A comparative experimental study of the isothermal shear and uniaxial elongational rheological properties of low density, high density and linear low density polyethylenes, J. Non-Newtonian Fluid Mech. 19, 251-274 (1986). 

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