A polymer alloy composition including: (a) a fluoropolymer selected from fluorinated ethylene propylene (FEP), perfluoroalkoxy alkane (PFA), ethylene tetra-fluoroethylene (ETFE), and a terpolymer of ethylene, tetrafluoroethylene, and hexafluoropropylene (EFEP); (b) a compatibilizing agent; and (c) a polyether imide (PEI) or polyimide (PI). Also disclosed is a method of forming a thermoplastic alloy. The polymer alloy may be used to form various extruded workpieces including, for example, a bag, film, container, filament, food package, coating (such as a coating or jacketing for a wire), powder for powder electrostatic powder coating, powder for dispersions, compression molded and various injection molded parts.