Published 21/04/2021

High density polyethylene

HIGH DENSITY POLYETHYLENE GEOMEMBRANES (HDPE)

What are High Density Polyethylene Geomembranes?

HDPE geomembranes gained popularity over traditional PVC geomembranes in the early 1980s due to their high chemical resistance, their durability and their ability to be thermally welded rather than adhesively bonded. At that time, PVC geomembrane welds delaminated while HDPE thermal fusion welding did not.

In practice, HDPE is currently the most widely used material for geomembrane manufacture. High Density Polyethylene (HDPE) is a thermoplastic polymer obtained by the polymerisation of ethylene. As one of the most versatile plastic materials, HDPE plastic is used in a wide variety of applications, especially in hazardous waste containment and water storage.

Known for its excellent tensile strength and high strength to density ratio, HDPE has a high resistance to impact, ultraviolet radiation, weathering and corrosion.

HDPE geomembranes are of obligatory application and have become the world standard for environmental protection: new cells and sealing of landfills and in general all those applications in which the conjunction of three fundamental properties is required: maximum chemical resistance, maximum resistance to weathering (ultraviolet radiation and ageing due to atmospheric thermal cycles) and impenetrability to most gases which, in this type of application, are usually present together with the product to be contained.

High density polyethylene uses

By extension and given its speci?c characteristics, it is also the product par excellence in applications for Water Storage and Hydraulic Works in general (canals, lagoon purification, golf course lakes, aquaculture...).

These are some of the most common applications of HDPE geomembranes:

• Landfill - solid waste.
• Landfill - liquid waste.
• Landfill capping.
• Biogas digesters.
• Cutoff Walls.
• Secondary containment.
• Heap Leach Pads.
• Tailings dams.
• Red mud dams.
• Mining process ponds.
• Water ponds.
• Channels and Water Conveyance.
• Evaporation ponds.
• Aquaculture.
• Ornamental lakes.
• Other hydraulic and geotechnical applications.
• Erosion Control.

What are the benefits of HDPE geomembranes?

High Density Polyethylene Geomembranes (HDPE) manufactured by ATARFIL have proven to be able to offer maximum efficiency thanks to their high strength and durability, they are suitable for the protection of the environment from toxic waste in the short, medium and long term.

One of the most outstanding properties of HDPE geomembranes is their resistance to Stress Cracking (SCR). SCR is the property of HDPE that determines its long-term mechanical durability and its resistance to mechanical damage due to stresses imposed during welding.  This problem is mitigated by ATARFIL HD geomembrane with a resistance to stress cracking (>3000h).

Properties of High Density Polyethylene, HDPE

One of the main benefits of HDPE comes from its malleability.  Due to its high melting point, HDPE remains rigid up to very high temperatures. However, once it has reached its melting point, the plastic material can be moulded quickly and efficiently.

High density polyethylene resists mould, corrosion and rot. HDPE can withstand most strong mineral acids and bases and has excellent resistance to chemicals found naturally in soil. In addition, the material is virtually impervious to most common chemicals, water, solvents, acids, gases, detergents and cleaning fluids.

The density of HDPE can range from 0.93 to 0.97 g, although the density of HDPE is only marginally higher than that of LLDPE (linear low density polyethylene), however, the linear structure of HDPE shows that the material has little branching, which gives it stronger intermolecular forces and higher tensile strength than LLDPE.

It is for this reason that a 60 gram HDPE container can safely hold almost four litres of liquid or approximately three and a half kilograms in weight.

Considering the amount of plastic we use in our daily lives, one of the most important factors when deciding on a plastic material is whether it is easily recyclable.  High density polyethylene is one hundred percent recyclable, so it has the advantage of being an environmentally responsible material.

1. Durability