Synonyms: 2,5-Furandione, polymer with methoxyethene, ester with .alpha.-(9Z)-9-octadecenyl-.omega.-hydroxypoly(oxy-1,2-ethanediyl), ammonium salt;2,5-Furandione, polymer with methoxyethene, ester with (Z)-α-9-octadecenyl- ω-hydroxypoly(oxy-1,2-ethanediyl), ammonium salt