High-density polyethylene geomembranes

Hsuan YG and Koemer RM (1998) Antioxidant Depletion Lifetime in High Density Polyethylene Geomembranes. Journal of Geotechiucal and Geoenviron-menlal Engineering 124 532-541... 

Soong T-Y and Koemer RM (1999) Behavior of waves in high density polyethylene geomembranes a laboratory study. Geotextiles and Geomembranes 17 81-104... 

Medium Density High Density Polyethylene MDPE (or MDHDPE) is produced by copolymerization of ethylene with a-olefins using Ziegler-Natta, supported chromium or single site catalysts. MDPE cannot be produced by free radical polymerization. MDPE has a linear structure similar to LLDPE, but comonomer content is lower. Density is typically 0.93-0.94 g/cm. MDPE is used in geomembrane and pipe applications. 

GRI (2006) GRI Standard GM13 Test Properties, Testing Frequency and Recommended Warrant for High Density Polyethylene (HDPE) Smooth and Textured Geomembranes. Geosynthetic Institute (GSI), Folsom, USA... 

This overview of the various cases of repercussions of chemicals on HDPE materials justifies the conclusion already addressed several times that, though HDPE geomembranes are not entirely inert, they are extraordinarily resistant to a broad spectrum of high-concentration chemicals at normal temperatures. This can also be seen by the assessment of chemical resistance as described in DIN 8075-Attachment 1 1984 High Density Polyethylene (HDPE) Pipes Chemical Resistance of Pipes and Fittings. The standard classifies for a large number of chemicals whether HDPE materials are resistant, only conditionally resistant or are not resistant at all... 

Although woven fabrics can be impregnated and coated in bitumen to give a bituminous geomembrane (BGM), the geomembranes widely used as impervious sheets are largely made from high-, medium-, and low-density polyethylene (HDPE, MDPE, LDPE), but PP, ethylene propylene diene monomer (EPDM) and PVC are used as alternatives for some applications. 

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