Development of toxicity tests for Polyurethane foams

Abstract

Polyurethanes (PUs) are a special class of polymeric materials that differ significantly from most other types of plastic in many aspects. They can be utilized in a wide range of products, including paints, coatings, elastomers, insulators, elastic fibers, and foams. PU foams are especially important as part of various convenience products. PU products often end up in landfills when they are no longer useful and can release toxic compounds when damaged by humans or microbes. Therefore, the ecotoxicological assessment of PU foams is essential. In this paper, five PU foam samples were prepared with different NCO indices (NCO-0.8, 0.9, 1.0, 1.1, and 1.2) and together with the Control sample (a previously tested non-toxic foam sample) were applied to develop toxicity tests procedure, while intentionally prepared Toxic foam has been used to verify the accuracy of the developed testing procedure. Two test organisms were successfully applied, Sinapis alba (white mustard) seeds and Escherichia coli (non-pathogenic) bacterial model organisms, and toxicity tests were adapted for the examination of PU-derived substances. Regarding Sinapis alba test, the highest NCO index (NCO-1.2) significantly reduced root length by 9.8 % compared to the Control sample. In the bacterial test, it was observed that the samples containing NCO-1.1 and NCO-1.2 had lower colony numbers (5.0 × 108 and 4.9 × 108 CFU/mL respectively) in comparison to the Control plate (9.6 × 108 CFU/mL). All in all, two toxicity tests were successfully adapted for PU foams, and both are applicable in their ecotoxicological assessment.