Use of vinylphosphonic acid for the preparation of biodegradable copolymers, and their use for the exploration and production of oil and natural gas

The invention relates to the use of vinyl phosphonic acid or a salt thereof for improving the biodegradability of mixed polymers which are from 25 to 99.5 wt .-% of structural units of one or more monomers selected from the group consisting of compounds of the formula 1 formula 3 wherein R wherein n is 3, 4 or 5, and formula 5 wherein X is OH or NR