An anhydride-functional polymer obtained by polymerizing under free radical addition polymerization reaction conditions, of a monomer mixture comprising:(i) 20 to 75 weight percent of an alkenyl succinic anhydride having the structure: ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 are each independently hydrogen or alkyl or substituted alkyl of 1 to about 30 carbons; and(ii) 25 to 80 weight percent of at least one (meth)acrylic monomer copolymerizable with the alkenyl succinic anhydride; and, optionally,(iii) 0 to 75 weight percent of at least one unsaturated monomer, other than a (meth)acrylic monomer, which is copolymerizable with the anhydride and the (meth)acrylic monomer; and wherein at least part of the monomer mixture comprises acrylic monomers or monomers having allylic hydrogens.