Fuente: WIPO "circular economy" A polymer of at least one N-vinylformamide monomer, wherein the N-vinylformamide monomer results from a reaction between an acetaldehyde and a formamide, wherein the acetaldehyde and/or the formamide contains 14C, such that the acetaldehyde and/or the formamide contains a bio-sourced carbon content of between 40 wt % and 100 wt % relative to total carbon mass of the acetaldehyde and/or the formamide, respectively, wherein the 14C and the bio-sourced carbon content are measured by a standard ASTM D6866-21 Method B.