A method for making a pressure sensitive adhesive comprising: (a) reacting (i) at least one dibasic acid or anhydride thereof with (ii) at least one epoxide having at least two epoxy groups, one diol or polyol, or one diamine at a stoichiometric molar excess of reactive carboxylic acid groups relative reactive epoxy groups, hydroxyl groups or amine groups to produce a thermoplastic prepolymer or oligomer capped with a carboxylic acid group at both prepolymer or oligomer chain ends, or a thermoplastic branched prepolymer or oligomer with at least two of the prepolymer or oligomer branches and chain ends capped with a carboxylic acid group; and (b) curing the resulting carboxylic acid-capped prepolymer or oligomer with at least one polyfunctional epoxy to produce a pressure sensitive adhesive, wherein the polyfunctional epoxy is not an epoxidized vegetable oil. A method for making a pressure sensitive adhesive comprising: (a) reacting at least one dibasic acid or anhydride thereof with at least one epoxide having at least two epoxy or oxirane groups at a stoichiometric molar excess of reactive epoxy or oxirane groups relative reactive carboxylic acid groups to produce a thermoplastic prepolymer or oligomer capped with an epoxy or an oxirane group at both prepolymer or oligomer chain ends, or a thermoplastic branched prepolymer or oligomer with at least two of the prepolymer or oligomer branches and chain ends capped with an epoxy or oxirane group; and (b) (i) curing the resulting epoxy-capped prepolymer or oligomer with at least one polybasic acid, or (ii) thermally curing the resulting epoxy-capped prepolymer or oligomer, to produce a pressure sensitive adhesive.