Rheological and mechanical properties of LDPE/HDPE blends

Melt rheology and mechanical properties of binary blend of low-density polyethylene (LDPE) and high-density polyethylene (HDPE) have been investigated. Four different wt fractions of blends containing LDPE/HDPE (20/80, 40/60, 60/40, and 80/20) were prepared. Cole-Cole plots [storage melt viscosity (eta') vs. loss melt viscosity (eta')] and relation between storage melt viscosity (eta') with frequency (omega) and blend composition were constructed. Miscibility of blends was established from rheological data. Impact strength of the blends increased with increasing LDPE concentration, whereas tensile strength shows the opposite trends. Percentages of the crystallinity of the blends were calculated by both the differential scanning calorimetry and wide-angle X-ray scattering methods, which show that the percentage of crystallinity decreased with increasing LDPE concentration, but the rate of crystallization of HDPE phase was unaffected.