Comonomer compositions for production of imide-containing polyamino acids

A mixture of aspartic acid and a salt of aspartic acid which comprises free aspartic acid and a salt of aspartic acid having a cation which does not volatilize in a molar ratio of 1:4 to 4:1.

A solution of a salt of aspartic acid having a non-volatilizable cation and a salt of aspartic acid having a volatilizable cation.

A mixture of an acid salt of aspartic acid and aspartic acid wherein positively charged amino groups of the aspartic acid molecules are balanced substantially only by salt formation with other aspartic acid molecules or with the anions of said acid salt of aspartic acid.

A method for preparing a copolymer containing copolymerized aspartate units and succinimide units which comprises:

• heating to polymerize a comonomer mixture of aspartic acid and a salt of aspartic acid, which comonomer mixture was prepared by drying a solution of salt of aspartic acid having a cation which does not volatilize during the drying and a salt of aspartic acid having a cation which at least partially volatilizes to free aspartic acid during the drying.

A copolymer containing copolymerized aspartate units and succinimide units in a ratio of from 1:4 to 4:1 or a derivative of this copolymer derivatized by reacting an amino group-containing compound, —OH group-containing compound or other nucleophilic group-containing compound with at least one succinimide unit of the copolymer.

A copolymer containing copolymerized aspartate units and succinimide units in a ratio of from 1:10 to 10:1 or a derivative of this copolymer derivatized by reacting an amino group-containing compound, —OH group-containing compound or other nucleophilic group-containing compound with at least one succinimide unit of the copolymer;

• provided that the copolymer is not a copolymer resulting from a process of adjusting the pH of a solution of aspartic acid with sodium hydroxide to a pH of from 3-7, drying the solution to a solid and then heating the solid to polymerize.

A copolymer containing copolymerized aspartate units and succinimide units in a ratio of from 1:10 to 10:1 or a derivative of this copolymer derivatized by reacting an amino group-containing compound, —OH group-containing compound or other nucleophilic group-containing compound with at least one succinimide unit of the copolymer, wherein the copolymer is in isolated form.