Thermally stable, highly fused imide compositions

Claim 2

A thermally stable imide polymer consisting essentially of repeating units having the following formula: ##STR7## wherein the imido nitrogen atoms are connected to the 4,4' or the 5,5' positions of the biphenyl linkage containing the 2,2'-phenylethynyl groups, and wherein R is ##STR8## and n has a value such that the polymer has an inherent viscosity of about 0.1 to 2.0 as measured in N,N'-dimethylacetamide at 30° C.

Claim 3

The imide polymer according to claim 1 in which the imido nitrogens are connected to the 5,5' positions of the biphenyl linkage and wherein R is ##STR9##

Claim 4

The imide polymer according to claim 1 in which the imido nitrogens are connected to the 5,5' positions of the biphenyl linkage and wherein R is ##STR10##

Claim 5

The imide polymer according to claim 1 in which the imido nitrogens are connected to the 4,4' positions of the biphenyl linkage and wherein R is ##STR11##

Claim 6

The imide polymer according to claim 1 in which the imido nitrogens are connected to the 4,4' positions of the biphenyl linkage, and wherein R is ##STR12##

Claim 7

The imide polymer according to claim 1 in which the imido nitrogens are connected to the 4,4' positions of the biphenyl linkage, and wherein R is ##STR13##

Claim 8

A process for preparing a thermally stable imide polymer which comprises the steps of mixing in an aprotic solvent selected from the group consisting of N,N'-dimethylformamide, N,N'-diethylformamide, N,N'-dimethylacetamide, N,N'-diethylacetamide, N-methyl-α-pyrrolidone, tetramethylurea, hexamethylphosphoramide, and tetramethylene sulfone at about room temperature equimolar amounts of (1) 2,2'-bis(phenylethynyl)-4,4'-diaminobiphenyl or 2,2'-bis(phenylethynyl)-5,5'-diaminobiphenyl and (2) an aromatic dianhydride having the following formula: ##STR14## adding to the mixture about 20 to 150 percent molar excess of acetic anhydride, based on the number of moles of (1) or (2); heating the resulting reaction mixture at about 120° to 140° C for a period of about 1 to 2 hours; and recovering an imide polymer.

Claim 9

A process for preparing a thermally stable imide polymer which comprises the steps of mixing in an aprotic solvent selected from the group consisting of N,N'-dimethylformamide, N,N'-diethylformamide, N,N'-dimethylacetamide, N,N'-diethylacetamide, N-methyl-α-pyrrolidone, tetramethylurea, hexamethylphosphoramide, and tetramethylene sulfone at about room temperature equimolar amounts of (1) 2,2'-bis(phenylethynyl)-4,4'-diaminobiphenyl or 2,2'-bis(phenylethynyl)-5,5'-diaminobiphenyl and (2) an aromatic dianhydride having the following formula: ##STR14## adding to the mixture about 20 to 150 percent molar excess of acetic anhydride, based on the number of moles of (1) or (2); heating the resulting reaction mixture at about 120° to 140° C for a period of about 1 to 2 hours; and recovering an imide polymer.

Claim 10

The process according to claim 7 in which equimolar amounts of 2,2'-bis(phenylethynyl)-5,5'-diaminobiphenyl and bis[4-(3,4-dicarboxyphenoxy)phenyl]sulfone dianhydride are mixed.

Claim 11

The process according to claim 7 in which equimolar amounts of 2,2'-bis(phenylethynyl)-5,5'-diaminobiphenyl and 2,2'-bis[4-(3,4-dicarboxyphenoxy)phenyl]hexafluoropropane dianhydride are mixed.

Claim 12

The process according to claim 7 in which equimolar amounts of 2,2'-bis(phenylethynyl)-4,4'-diaminobiphenyl and bis[4-(3,4-dicarboxyphenoxy)phenyl]sulfone dianhydride are mixed.

Claim 13

The process according to claim 7 in which equimolar amounts of 2,2'-bis(phenylethynyl)-4,4'-diaminobiphenyl and 2,2'-bis[4-(3,4-dicarboxyphenoxy)phenyl]hexafluoropropane dianhydride are mixed.

Claim 14

The process according to claim 7 in which equimolar amounts of 2,2'-bis(phenylethynyl)-4,4'-diaminobiphenyl and bis[4-(3,4-dicarboxyphenoxy)phenyl]sulfide dianhydride are mixed.