HDPE question

From the GMA Techline

Subject: HDPE question— I am a high school student doing a science project that is testing the chemical resistance of HDPE. Since we may not be able to test a 60-mil HDPE used in landfills, I was wondering about other products made from HDPE that could serve as a substitute. Would plastic bags, such as those from a store (also made from HDPE) be comparable to landfill HDPE (other than the thickness) as far as a comparison? And would tests using these bags be applicable to the chemical resistance/ability to resist permeation of HDPE used in landfills? (Brian, New York)

Reply: Thank you for a nice question. Plastic trash bags are, indeed, of the type of HDPE geomembranes from a resin perspective. The major differences are the thickness and the addition of additives in the geomembranes for longer lifetime and durability.

It is this second aspect that will make any durability testing on trash bags give lifetimes far shorter than the geomembranes. (Thickness is another issue but can be somewhat accounted for by proper scaling.)

Regarding additives, the geomembranes use antioxidants for longer lifetimes, and these [additives] are not used in trash bags. Thus, you might come close in mechanical property comparisons (as mentioned, with proper scaling), but your lifetime prediction is not possible.

Good luck with your project.

Bob Koerner | GMA Techline