A copolymer composition that includes a copolymer comprised of at least 30 mol % of residues having the following alternating residues from a donor monomer and from an acceptor monomer. The copolymer contains at least 15 mol % of an isobutylene type donor monomer and at least 15 mol % of an acrylic monomer as an acceptor monomer. The copolymer is substantially free of maleate or fumarate monomer segments and the copolymer composition is substantially free of Lewis acids and transition metals. Also disclosed is a thermosetting composition that includes a reactant comprising functional groups, a crosslinking agent having at least two functional groups that are reactive with the functional groups first reactant, and a copolymer flow control agent that includes the copolymer composition as well as substrates coated with the thermosetting composition.