The present disclosure provides methods for modifying polymeric resin materials after polymerization to make fine adjustments in the chemical or physical properties of the resin, or in modifying the structure of the polymer chains. The resulting resins may be useful in forming toner particles. In embodiments, a polymeric resin may have epoxy groups added to its backbone to increase its melting point. The resulting polymer, sometimes referred to herein as an epoxidized polymer, may, in turn, be reacted with wax-like components, to increase the compatibility of the polyester with waxes utilized in forming toner particles. In other embodiments, the resulting epoxidized polymer may be reacted with components possessing carboxylic acid groups to adjust the acid value and weight average molecular weight of the resin.