Connecting the complex microstructure of LDPE to its rheology and processing properties a combined fractionation and modelling approach.

Well-defined mini-plant low density polyethylene samples were fractionated preparatively according to their crystallizability preparative temperature rising elution fractionation and according to molecular weight preparative solvent gradient fractionation (pSGF). Rheology of the fractions was measured in both the small amplitude oscillatory shear (SAOS) and the non-linear extension regimes. The linear and non-linear rheology of the pTREF fractions were dominated by molecular weight effects, while the impact of the higher degree of long chain branching for the pSGF fractions with higher molecular weights was observed in van Gurp-Palmen plots and in strain hardening behavior in the extensional rheology measurements.