Q: Infrequently, I make a note of geosynthetic products manufactured using acrylonitrile butadiene styrene (ABS) (e.g., geogrid, binding line, a few molded specialty products). Can you provide a summary of most of the geosynthetic product types using ABS, as well as the general benefits and limitations of ABS geosynthetics?
A: Thank you for your GMA Techline question about ABS geosynthetics. ABS—chemical formula [(C8H8)x · (C4H6)y · (C3H3N)z] is a common thermoplastic polymer made by polymerizing styrene and acrylonitrile in the presence of polybutadiene. It provides favorable mechanical properties, such as impact resistance, toughness and rigidity when compared with other common polymers. Even though ABS plastics are used largely for mechanical purposes, they have been used in geosynthetics such as geopipes, geogrids, cores of geocomposites and geocells. ABS geosynthetics can be recycled, although it is not accepted by all recycling facilities. It is manufactured in a variety of grades, which can complicate recycling efforts.
ABS polymers are resistant to aqueous acids, alkalis, concentrated hydrochloric and phosphoric acids, and animal, vegetable and mineral oils. But they are swollen by acetic acid, carbon tetrachloride and aromatic hydrocarbons, and are attacked by concentrated sulfuric and nitric acids. They are soluble in esters, ketones (such as acetone), chloroform and ethylene dichloride. They offer poor resistance to chlorinated solvents, alcohols and aldehydes. All of this indicates that they are not the best choice for landfill applications and some uses in the transportation sector.
ABS is flammable when it is exposed to high temperatures. It will melt and then boil, at which point the vapors burst into intense, hot flames. ABS combustion does not typically produce any persistent organic pollutants, and the most toxic products of its combustion or pyrolysis are carbon monoxide and hydrogen cyanide. Unfortunately, ABS is damaged by sunlight, and, when it decomposes, it reverts into its constituents, which are possibly carcinogenic.
Response from questioner
Thank you for your unexpectedly timely and detailed response far beyond what I had expected.
You confirmed that the range of geosynthetic product usage corresponds to my impressions over the years.
The only point in your presentation with which I may take exception is the UV deterioration of ABS plastics. I have worked with ABS in various applications (marine, industrial structural components, etc.) over the last 40 years. I am aware that UV resistance of many thermoplastics can be enhanced by various proprietary stabilizers, which, unbeknown to me, must have been the reason that so many of the ABS items lost little of their mechanical properties due to daily exposure to sunlight, except a bit of brittling due to aging, seemingly less than, for example, polyvinyl chloride (PVC).
Years ago, I adapted an ABS specialty tools/parts box of aircraft industry origin for use as a marine battery box for four large lead acid batteries. The combined spilled/sloshed sulfuric acid and marine exposure took a toll on everything, but the box held up well over the years with only some interior portions developing a surficial slime that is easily removed with a wire brush.
Keep up the good work.
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