Abstract: Monomeric esters of fumaric, maleic, citraconic, mesaconic, itaconic, aconitic, or methylene malonic acid and alcohols of the formula C.sub.m F2.sub.m+1 C.sub.n H2.sub.n OH and mercaptans of the formula C.sub.m F2.sub.m+1 C.sub.n H2.sub.n SH form homopolymers and form copolymers with other ethylenically unsaturated comonomers. The polymers obtained have valuable soil repellent properties and are especially useful in textile finishes. Preferred compounds are bis (1,1,2,2-tetrahydroperfluorononyl) fumarate and bis (1,1-dihydroperfluorooctyl) fumarate.