A support material for printing a support structure (82) with an electrophotography-based additive manufacturing system (10), the support material including a composition having a charge control agent and a thermoplastic copolymer having aromatic groups, (meth)acrylate -based ester groups, carboxylic acid groups, and anhydride groups, with a high anhydride conversion. The composition is provided in a powder form having a controlled particle size, and the support material is configured for use in the electrophotography-based additive manufacturing system (10) having a layer transfusion assembly (20) for printing the support structure (82) in a layer-by-layer manner, and is at least partially soluble in an aqueous solution.