Synthesis and characterization of poly(ether ketone) poly(ether sulfone) alternating and sequential copolymers by electrophilic reactions

The synthesis aqd NMR characterization of some poly(ether ketone)/poly(ether sulfone) (PEK/PES) alternating copolymers together with a series of sequential homopolymers containing CO, 0, S and SO, bridging groups, all obtained by electrophilic condensation reactions using phosphorus pentoxide/methanesulfonic acid as dehydrating agent, is here reported. Properties of such polymers are compared with those of their model compounds from which it can be inferred that both proton and carbon chemical shifts are very sensitive to the electronic environment generated by the 0, S, CO and SO, bridges. Differential scanning calorimetry indicates that our polymers are essentially amorphous irrespective of the bridging sequence. From viscosity measurements the molecular weights of these copolymers are judged to be very low.