Anomalous rheological response for binary blends of linear polyethylene and long-chain branched polyethylene

The rheological properties are studied for binary blends composed of a low‐density polyethylene (LDPE) and a linear polyethylene. It is found that some blends exhibit higher oscillatory shear moduli and drawdown force than the individual pure components, demonstrating that relaxation mechanism with longer characteristic time appears in the blend. The anomalous rheological behavior is detected more clearly for the blends with autoclave‐LDPE than those with tubular‐LDPE. Furthermore, the number of short‐chain branches in a linear polyethylene has no influence on the rheological properties of the blends, suggesting that the phase separation will not be responsible for the anomalous behavior. It is also found that blends of autoclave‐LDPE and tubular‐LDPE show no synergetic effect. © 2008 Wiley Periodicals, Inc. Adv Polym Techn 26:173–181, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20100