Abstract: An anhydride-functional polymer is obtained by at least partially hydrogenating an unsaturated polymer which was obtained by reacting under ene reaction conditions:(i) an unsaturated anhydride having the structure: ##STR1## wherein R.sub.1 and R.sub.2 are each independently hydrogen, alkyl of 1 to about 6 carbons, or alkoxy of 1 to about 6 carbons, or a halogen; and(ii) at least one polyolefin having at least two carbon-carbon double bonds in the polyolefin backbone and having an average of at least three carbon atoms in the polyolefin backbone between the carbon-carbon double bonds.