A process for forming an end capped polyimide of formula (IB):
- wherein:
- m is an integer of at least 50;
- X is derived from one or more dianhydrides selected from the group consisting of:
- 1H,3H-benzo[1,2-c:4,5-c′]difuran-1,3,5,7-tetraone (PMDA);
- 4-methyl-1H,3H-benzo[1,2-c:4,5-c′]difuran-1,3,5,7-tetraone;
- 5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione) (6FDA);
- and
- 5,5′-(perfluoropentane-3,3-diyl)bis(isobenzofuran-1,3-dione);
- Y is derived from one or more diamines selected from the group consisting of:
- 4,4′-([1,1′-biphenyl]-4,4′-diylbis(oxy))bis(3-(trifluoromethyl)aniline) (6BF);
- 2,2′-bis(trifluoromethyl)-[1,1′-biphenyl]-4,4′-diamine (PFMB);
- 4,4′-methylenebis(2,6-dimethylaniline) (DO3);
- 2-(4-aminophenyl)benzo[d]oxazol-5-amine (BZXPh-5);
- 2-(4-aminophenyl)benzo[d]oxazol-6-amine (BZXPh-6);
- benzo[d]oxazole-2,5-diamine (BZX-5);
- and
- benzo[d]oxazole-2,6-diamine (BZX-6);
- and
- R1 and R2 are the same or different and each independently of one another selected from the group consisting of hydrogen, linear or branched (C1-C16)alkenyl, hydroxy(C1-C12)alkenyl, perfluoro(C1-C12)alkenyl, and (C6-C10)aryl(C1-C3)alkenyl;
- and with the proviso that R1 and R2 are not both hydrogen;
- comprising:
- reacting the dianhydride with the diamine and a compound of formula (II):
- wherein R1 and R2 are as defined above, all of which dissolved in N-methyl-2-pyrrolidone at ambient temperature to form a polyamic acid;
- reacting the polyamic acid dissolved in cyclopentanone with acetic anhydride in the presence of pyridine at a temperature of about 90° C. for about four hours in nitrogen atmosphere and cooling to form the polyimide of formula (IB), which is soluble in an organic solvent selected from the group consisting of N-methyl-2-pyrrolidone (NMP), y-butyrolactone (GBL), N,N-dimethylacetamide (DMAc), propylene glycol monomethyl ether acetate (PGMEA), dimethyl sulfoxide (DMSO), cyclopentanone, cyclohexanone, 2-butanone and 2-heptanone and mixtures in any combination thereof;
- and wherein the amount of compound of formula (II) used to form the end capped polyimide of formula (IB) is about 2.5 mole percent based on total moles of dianhydride, diamine and the compound of formula (II).