Biodegradable polymeric materials based on polyether glycols, processes for the preparation thereof and surgical articles made therefrom

A multiblock copolymer useful for the manufacture of bioabsorbable surgical articles, having a general repeating unit I ##STR14## wherein R is an alkylene group, R.sub.1 is hydrogen or methyl groups, m is a positive integer, and a and b are zero or positive integers, the case where a and b are simultaneously zero being excluded.

A multiblock copolymer having the following general formula:

• ##STR15## wherein R represents an alkylene group, R.sub.1 is hydrogen or methyl groups and R' is hexamethylene, 4,4'-diphenylmethane, toluene, naphtalene, 4,4'-dicyclohexylmethane, cyclohexyl, 3,3'-dimethylphenyl, 3,3'-dimethyl-diphenylmethane, 4,6'-xylylene, 3,5,5-trimethylcyclohexyl, 2,2,4-trimethyl-hexamethylene and p-phenylene, or diisocyanate-terminated polyalkylene glycol chains comprising a central polyalkylene glycol chain capped by two diisocyanate compounds of the above, x and y are identical or different positive integers and m is a positive integer.

A process of producing a multiblock copolymer having a general repeating unit I ##STR18## wherein R is an alkylene group, R.sub.1 is hydrogen or methyl groups, m is a positive integer, and a and b are zero or positive integers, the case where a and b are simultaneously zero being excluded, produced by adding monomeric .alpha.-hydroxy carboxylic acids of the formula ##STR19## to hydroxyl-ended poly(alkylene glycol) chains, the polycondensation reaction taking place in the presence of an esterification promoting catalyst at a temperature of about 120.degree. to 160.degree. C., subsequently raising the temperature to about 200.degree. C. for about 16 hours, with constant flow of dry nitrogen and then lowering the temperature to about 135.degree. C. while a 5 mm Hg vacuum is applied for about 4 hours.

A process for chain extending triblock copolymers of formula IV ##STR20## wherein R, X, y and m are as defined, said triblock polymers, which are produced by the polycondensation reaction of monomeric .alpha.-hydroxy carboxylic acid, having the formula ##STR21## in the presence of hydroxyl-terminated poly(alkylene glycol) chains, are extended by adding to the polymers produced thereby, a diisocyanate chain extension agent of general formula OCN--R'--NCO, wherein R' is hexamethylene, 4,4'-diphenylmethane, toluene, naphtalene, 4,4'-dicyclohexylmethane, cyclohexyl, 3,3'-dimethylphenyl, 3,3'-dimethyl-diphenylmethane, 4,6'-xylylene, 3,5,5-trimethylcyclohexyl, 2,2,4-trimethyl-hexamethylene and p-phenylene, or diisocyanate-terminated polyalkylene glycol chains comprising a central polyalkylene glycol chain capped by two diisocyanate compounds of the above, x and y are identical or different positive integers and m is a positive integer.

A multiblock copolymer having the following general formula III ##STR22## wherein R represents an alkylene group, R.sub.1 is hydrogen or methyl groups, R" is an alkylene saturated or unsaturated group or an aromatic ring, x and y are identical or different positive integers, and m is a positive integer.