HDPE Particles

Molecular mass

Higher molecular weights result in higher polymer viscosities, although viscosity is also related to the temperature and shear rate used for testing. The molecular weight of the material is characterized by rheological or molecular weight measurements.HDPE Particles grades generally have molecular weights in the range of 40,000 to 300,000, with the weight-average molecular weights roughly corresponding to the melt index range, i.e., from 100 to 0.029 g/10min (230°C, 2.16 kg). Typically, higher Mw (lower melt index MI) enhances melt strength, better toughness, and ESCR, but higher Mw makes the process more difficult or requires higher Mw. However, higher Mw makes the process more difficult or requires higher pressures or temperatures.

Molecular Weight Distribution (MWD): The WD of PE varies from narrow to broad depending on the catalyst used and the process.

The most commonly used index for measuring MWD is the heterogeneity index (HI), which is equal to the weight average molecular weight (Mw) divided by the number average molecular weight (Mn). This index ranges from 4 to 30 for all HDPE Particles grades.Narrow MWD provides low warpage and high impact in the molding process. Medium to wide MWDs provide processability for most extrusion processes. Wide MWDs also improve melt strength and creep resistance.