Abstract: Macrocyclic polyimide oligomers are converted to linear polyimides by heating with a primary amine in the presence of a tertiary amine, tertiary phosphine, quaternary ammonium salt, quaternary phosphonium salt or hexaalkylguanidinium salt or heterocyclic analog thereof as a macrocyclic polyimide polymerization catalyst.

Abstract: Macrocyclic polyetherimide oligomer compositions are prepared by a displacement reaction at a temperature in the range of about 200.degree.-225.degree. C. between at least one fluorinated aromatic phthalimide and at least one phenolic trialkylsilyl ether compound. Preferably, a bis-fluoroimide and a bis-trialkylsilyl ether of a dihydroxyaromatic compound such as resorcinol are employed. The reaction is conducted by maintaining reagents A and B in high dilution in a dipolar aprotic organic liquid such as N-methylpyrrolidone, and in the presence of a catalytic amount of at least one substantially soluble fluoride. Preferably, a mixture of reagents A and B is added to solvent containing the catalyst.

Abstract: Macrocyclic polyimide oligomers are prepared by the reaction of at least one diamine with at least one tetracarboxylic acid or dianhydride thereof in equimolar amounts, under conditions of high dilution of said reagents. The macrocyclic oligomers are capable of conversion into linear polyimides by heating with a primary amine in the presence of a macrocyclic polyimide polymerization catalyst, typically an alkaline earth or transition metal or salt thereof.

Abstract: Macrocyclic polyimide oligomers are prepared by the reaction of at least one diamine with at least one tetracarboxylic acid or dianhydride thereof in equimolar amounts, under conditions of high dilution of said reagents. The macrocyclic oligomers are capable of conversion into linear polyimides by heating with a primary amine in the presence of a macrocyclic polyimide polymerization catalyst, typically an alkaline earth or transition metal or salt thereof.

Abstract: Polyarylene sulfides react with disulfides containing reactive functional groups, typically at temperatues within the range of about 225.degree.-375.degree. C., yielding reactively capped polyarylene sulfides. The preferred reactive functional groups are amino groups and carboxy groups and functional derivatives thereof.

Abstract: Polyarylene sulfides react with disulfides containing reactive functional groups, typically at temperatures within the range of about 225.degree.-375.degree. C., yielding reactively capped polyarylene sulfides. The preferred reactive functional groups are amino groups and carboxy groups and functional derivatives thereof.