Disclosed is a method for making nongelled addition polymers, especially carbamate functional additional polymers from linear unsaturated anhydrides. The method comprises reacting an unsaturated linear anhydride with an active hydrogen compound to provide two monomers comprising polymerizable C.dbd.C bonds, at least one of said monomers comprising an acid functional group; polymerizing the polymerizable C.dbd.C bonds of the two monomers to provide an acid functional polymerization product; and reacting the acid functional polymerization product with an epoxy functional compound to provide a nongelled addition polymer, wherein the disclosed method does not include a step comprising the physical removal of any acid functional monomers or polymerization products. Also disclosed is a curable coating composition containing the resulting carbamate functional polymer, as well as a coated substrate comprising a cured film resulting from the application and curing of the disclosed curable coating composition.