Molecular Weight Distribution and Melt Rheological Properties for High Density Polyethylenes

Rheological Method for Determining Molecular Weight and Molecular Weight Distribution

Melt Flow Indexer Evidence of High-Temperature Transitions in Molten High-Density Polyethylenes

A melt flow indexer (MFI) was used to investigate high-temperature transitions in melts of high-density polyethylene (HDPE). The MFI data were obtained in the range 190–230°C. These transitions were found in the MFI at about 210 and 225°C and reproduced in a Haake melt blender. Polystyrene was used in the blender experiment to demonstrate typical amorphous behavior. For HDPE melts, the MFI–temp...

Polyethylenes Modified by Irradiation and Organic Peroxide Treatment: Rheological Study

− A series of polyethylenes was obtained by modification of two commercial high-density polyethylenes. The organic peroxide concentrations and irradiation dosis used are below the critical ones that produce molecular networks. The molecular weights of the polymers increase, and the molecular weight distribution gets wider, as the concentration/dose increases. These results are a consequence of ...

Pii: S0032-3861(98)00318-8

Polyethylenes (PE) with long chain branching (LCB) densities up to 0.44 carbons/10 000 carbons and narrow molecular weight distributions were synthesized using a continuous stirred-tank reactor (CSTR) with the Dow Chemical’s constrained geometry catalyst system, CGCTi/TPFPB/MMAO, in Isopar E solution at 500 psig and 140–1908C. Rheological properties of these metallocene polyethylenes (mPE) were...

Mechanical, Rheological, and Bioactivity Properties of Ultra High-Molecular-Weight Polyethylene Bioactive Composites Containing Polyethylene Glycol and Hydroxyapatite

Ultrahigh-molecular-weight polyethylene/high-density polyethylene (UHMWPE/HDPE) blends prepared using polyethylene glycol PEG as the processing aid and hydroxyapatite (HA) as the reinforcing filler were found to be highly processable using conventional melt blending technique. It was demonstrated that PEG reduced the melt viscosity of UHMWPE/HDPE blend significantly, thus improving the extrudab...