Cross-linking of maleic anhydride polymers with bicyclic amide acetals

The process for cross-linking a maleic anhydide homopolymer or interpolymer with at least one other mono vinyl monomer comprising reacting said homopolymer or interpolymer with a bicyclic amide acetal conforming to the formula ##STR2## wherein R represents hydrogen or an alkyl group having from 1 to 18 carbon atoms, R' represents an alkyl group having from 1 to 18 carbon atoms or an aryl or alkaryl group having from 6 to 18 carbon atoms, and R" represents hydrogen or an alkyl group having from 1 to 18 carbon atoms, an aryl group having from 6 to 12 carbon atoms, or a hydrogen ether group having from 2 to 18 carbon atoms.