4. PP geomembranes

4.1 Composition

Polypropylene (PP) is a polyolefin like polyethylene. PP is a relatively rigid thermoplastic polymer.

The base material used in PP geomembranes is a copolymer of polypropylene (20%) and ethylene-propylene (80%). This copolymer has a degree of crystallinity of 5% and is flexible. As with HDPE, a melt flow index can be measured for the waterproof compound in PP geomembranes. This is measured at 230ºC, instead of 190ºC for HDPE.

The waterproof compound used in PP geomembranes comprises approx. 97% polypropylene-ethylene-propylene copolymer,...