Solvent-free, fine white powders of high molecular weight copolymers of maleic anhydride and a C1-C4 alky vinyl ether without odor or taste

A solvent-free process for obtaining solvent-free, fine white powders of high molecular weight alternating copolymers of maleic anhydride and a C1-C4 alkyl vinyl ether, without odor or taste, having the molecular structure (A-B)n, where A is maleic anhydride and B is alkyl vinyl ether, and n is an integer indicative of the molecular weight of the copolymer, and a specific viscosity >6 (1% w/vol in MEK, 25° C.), which consists essentially of precharging excess alkyl vinyl ether over the desired 1:1 mole ratio of A:B in the copolymer into a reactor, adding 0.01 to 0.1% by weight based on copolymer of a free radical initiator, heating the mixture to a reaction temperature of about 50° to 100° C., feeding molten maleic anhydride into the thus-charged reactor over a predetermined period of time, holding at about 50° to 1000° C., adding a food grade antioxidant stabilizer, stripping excess alkyl vinyl ether from the reaction product, and drying the copolymer obtained of any remaining traces of alkyl vinyl ether.