Carbon black absorbs UV before it can break polymer chains, so exposed HDPE liners and geonets can last for decades. Labs check both content, by driving off the polymer in a nitrogen-purged furnace and weighing the black residue, and dispersion, by looking at thin slices under a microscope for clumps. Poorly dispersed carbon black leaves unprotected zones and can start cracks.
Carbon black content passed at 2.4 percent, but the dispersion slide shows clumps, so hold the lot.
Also heard as
- CB
- carbon black content
Related terms
HDPE
High-density polyethylene: the stiff, chemically resistant polymer used for most landfill and mining geomembranes.
UV resistance
How much strength a geosynthetic keeps after exposure to ultraviolet light in an accelerated weathering test.
OIT
Oxidative induction time: a measure of how much antioxidant protection remains in a polyolefin geosynthetic.