Monomer BTDA, preparation

Monomers. BTDA and APA were obtained from Gulf Chemicals. BTDA was recrystallized from acetic anhydride prior to use, and APA was distilled under reduced pressure. Diamines la-d were prepared from 1-fluoro-4-nitrobenzene and the appropriate glycol according to the known procedure (4). 

A series of 15 wt % isomeric polyimide precursor resin solutions was prepared by the National Aeronautics and Space Administration Langley Research Center. The polymerization procedure has been described previously (2,3). The poly(amic-acid) resin solutions were made from 3,3, 4,4 -benzophenonetetracarboxylic acid dianhydride (BTDA), 4,4 -oxydiphthalic anhydride (ODPA), diaminobenzophenone (DABP), and methylenedianiline (MDA) monomers. 

A new aromatic diamine monomer with four pendant -CF3 groups was successfully synthesized by a three-step reaction using w(4-fluorophenyl)sulfone and A-bromosuccinimide as starting materials. Then, a series of fluorinated poly(ether sulfone imide)s was conveniently prepared from the diamine and three aromatic dianhydrides (BPDA, BTDA, and ODPA) via one-step solution polycondensation. 

Pis prepared with 4,4 -oxydianiline (ODA) and 3,3, 4,4 -benzo-phenone tetracarboxyhc dianhydride (BTDA) monomers, cf. Figure 6.1, can be loaded with 10 and 15 wt% tungsten nanoparticles that are treated with benzyl mercaptan. The 3,3, 4,4 -benzophenone tetra-carboxylic dianhydride and ODA monomers are reacted to form PI films that are flexible to the point of being creaseable. The nanocomposite films are effective as an electromagnetic radiation shield (5). 

Chen et al. [137] employed microwave irradiation for the preparation of amine-or anhydride-terminated hb-PIs. A BB 2-type triamine monomer, namely 2,4,6-tris (4-aminophenyl)pyridine (TAPP) (1-16, Scheme 9a), was synthesized under microwave irradiation to prepare a series of amine- and anhydride-terminated triphenylpyridine-containing hb-PIs by A2 + BB 2 polymerization. Several commercially available aromatic dianhydrides, namely pyromellitic dianhydride (PMDA, 1-23, Scheme 9b), BTDA, and ODPA, were used as A2 type monomers to react with the BB 2 type aromatic triamine (TAPP). The addition of dianhydride to triamine with a monomer molar ratio of 1 1 yielded the amine-terminated polymer, whereas the reverse monomer addition order with a molar ratio of 2 1 gave the anhydride-terminated polymer. Slow monomer addition was used to avoid any high local concentration. The authors kept the total solid content below 0.08 mol/L for the amine-terminated polymer and 0.06 mol/L for the anhydride-terminated polymer to prevent insoluble gels. During the whole polymerization, continuous microwave irradiation was employed to enhance the reactivity and... 

---