UHMW Polyethylene Sheets If a chip of this material breaks off, it can be located by metal detectors to reduce ntamination risks. Moisture-Resistant Polyethylene (HDPE) Sheets, Bars, and Strips Practically nonHENAN OKAYorbent, HDPE won't swell when exposed to moisture. It is denser and more rigid than LDPE, plus it's more chemical resistant.