Polyethylene (PE) is one of the simplest polymers that exist but also one that presents the best properties in order to form impermeable barriers.

The chemical structure (repeating unit) of polyethylene is:



The Polyethylene used for geomembranes comes in different types:

  • High density polyethylene (HPDE).
  • Linear low density polyethylene (LLDPE).
  • Very low density polyethylene (VLDPE).

In addition to the small differences in density between these types, those materials have different mechanical properties because they present a greater or smaller number of ramifications for each 1000 repeating units.

Thus, HDPE (few short ramifications) is the most rigid and has high mechanical resistance ones, the VLDPE (frequent and long ramifications) is very flexible, and the LLDPE (short ramifications; more than HDPE) is flexible but with mechanical properties similar to those of the HDPE.

The fusion point of polyethylene varies between 115 and 135 degrees Celsius, nevertheless the maximum recommended design temperature is approximately 70 degrees Celsius.