Binary blends of metallocene polyethylene with conventional polyolefins: Rheological and morphological properties

Abstract

The rheology and morphology of four sets of binary blends of polyethylene synthesized with metallocene catalysis (metallocene polyethylene: MCPE) with polyolefins prepared using Ziegler‐Natta catalysts have been investigated. The blend systems are MCPE with high density polyethylene (MCPE‐HDPE), polypropylene (MCPE‐PP), poly(propylene‐co‐ethylene) (MCPE‐CoPP), and poly(propylene‐co‐ethylene‐co‐1‐butylene) (MCPE‐TerPP). Cole‐Cole plots [storage melt viscosity (η′) versus loss melt viscosity (η″)], plots of the dynamic storage modulus (G′) versus the dynamic loss modulus (G″), and plots of the log melt viscosity (η*, η′, and η″) versus blend compositions were constructed. The morphology of the blends after microtoming and etching was studied. The phase morphology of MCPE‐HDPE appeared homogeneous, whereas the other three blends were heterogeneous. Rheological and morphological investigations indicated that the MCPE‐HDPE blend was miscible, but the other three blends were immiscible in the melt as well as in the solid state. These observations can be rationalized in terms of the similarity of the chemical structures of the polyolefins.

Melt miscibility of HDPE/UHMWPE, LDPE/UHMWPE, and LLDPE/UHMWPE blends detected by dynamic rheometer

“…Although it is an empirical method, it has been widely used to analyze the melt miscibility of polymer blends [14,15]. A smooth, semicircular shape of the plotted curves suggests good compatibility, i.e., phase homogeneity in the melt, and any deviation from this shape shows a heterogeneous dispersion and phase separation due to immiscibility.…”

Rheological behavior and mechanical properties of high‐density polyethylene blends with different molecular weights

“…7 The m-LLDPE/HDPE blend was also found to be miscible by rheological and morphological investigations. 35 Blends of various PEs are commonplace, in particular, mixtures of LPE with branched polyethylene (BPE). The phase behavior of LPE/BPE blends has been studied intensively by the study of the rheological properties, and phase separations in blends of LPE and BPE have focused on components different in molecular parameters.…”

Structural and rheological property relationship of bimodal polyethylene with improved environment stress cracking resistance

“…The phase behavior were analyzed using the Cole-Cole plots, representing the relation ship between the imaginary viscosity (η'') and real vis cosity (η'). Although it is an empirical method, it has been widely used to analyze the miscibility of polymer blends [37,38]. A smooth, semicircular shape of the plotted curves suggests good miscibility, i.e., phase homogeneity in the melt, and any deviation from this shape shows a heterogeneous dispersion and phase separation due to immiscibility.…”