The title of the paper at your link is "Acute toxic effects of polyethylene microplastic on adult zebrafish". Polyethylene[1] is not the same thing as Polyuret

The title of the paper at your link is "Acute toxic effects of polyethylene microplastic on adult zebrafish". Polyethylene[1] is not the same thing as Polyurethane[2]. [1] https://en.wikipedia.org/wiki/Polyethylene https://en.wikipedia.org/wiki/Polyethylene, [2] https://en.wikipedia.org/wiki/Polyurethane https://en.wikipedia.org/wiki/Polyurethane