화학공학소재연구정보센터
Journal of Applied Polymer Science, Vol.105, No.2, 309-316, 2007
Shear and elongational rheology of polyethylenes with different molecular characteristics. I. Shear rheology
Four metallocene polyethylenes (PE), one conventional low density polyethylene (LDPE), and one conventional linear low density polyethylene (LLDPE) were characterized in terms of their complex viscosity, storage and loss moduli, and phase angle at different temperatures. The effects of molecular weight, breadth of molecular weight distribution, and long-chain branching (LCB) on the shear rheological properties of PEs are studied. For the sparsely long-chain branched metallocene PEs, LCB increases the zero-shear viscosity. The onsets of shear thinning are shifted to lower shear rates. There is also a plateau in the phase angle, delta, for these materials. Master curves for the complex viscosity and dynamic moduli were generated for all PE samples. (c) 2007 Wiley Periodicals, Inc.