Process for the surface modification of a polyester substrate, such surface-modified substrate and its uses

A process is provided to covalently bind an amine-terminated polyamine to at least a part of the surface of a polyester substrate via an amidation reaction comprising the steps of a) providing a polyester substrate, b) providing an amine-terminated polyamine, c) coating the amine-terminated polyamine onto at least a part of the surface of the polyester substrate to result in a coated substrate, d) heating the coated substrate of step c) at a temperature T ranging from room temperature up to 130 DEG C for a reaction time ranging from 10 seconds up to 18 hours, e) removing physisorbed amine-terminated polyamine and f) drying. Furthermore, a polyester substrate comprising on at least a part of its surface an amine-terminated polyamine, which is covalently bound to the substrate via an amide bond, is provided and uses of said inventive substrate are described.