persulfates azo compounds and the like the reaction time will also vary depending upon other variables such as the temperature the catalyst and the desired extent of the polymerization it is generally desirable to continue the reaction until less than 0 5 of the vinyl ester remains unreacted under these circumstances a reaction time of about 6 hours has been found to be generally sufficient for complete polymerization but reaction times ranging from 2 to 10 hours have been used and other reaction times can be employed if desired crosslinking of the polymer having hydroxyl functionality and carboxyl functionality is achieved by reaction with at least two multifunctional reactants one capable of reacting with the hydroxyl functionality and the other with the carboxyl functionality one of the multifunctional components is a polyaldehyde and preferably a dialdehyde the other multifunctional component is a polyaziridine the operative level of each is controlled such that generally at least an effective amount or a stoichiometric amount is added to react with the hydroxyl and carboxyl functionality of the polymer and effect dual crosslinking to drive the reaction to completion in a short time as required on the production line an excess of one of the reactants is employed in crosslinking one end of the dialdehyde can react with the hydroxy functionality on the substrate e g a diol group of cellulose and the other.