Study on Uniaxial Elongational Viscosity and Vacuum Molding Processability of the PP/PE Blends

The relationship between uniaxial elongational viscosity and vacuum molding processability of the PP/PE blends were investigated. Propylene homo-polymer (PP) and 3 kinds of high pressure method low density polyethylene with different molecular weight (PE-A, PE-B, PE-C) were used. Materials were melt blended to the ratio of PP/PE=90/10, 80/20 and 70/30wt% for the experiments. The PP/PE blends showed strain hardening of uniaxial elongational viscosity, while PP showed no strain hardening. The strain hardening of PP/PE increased with increasing of the blend ratio of PE to PP, and the molecular weight of PE. The morphologies of PP/PE under uniaxial elongational flow were observed by TEM. For the samples with the lower molecular weight PE, the larger deformation of PE domain was observed. The deviation of thickness of the vacuum molding products decreased according to the increase of the strain hardening of PP/PE.